Going back for thirds: McGregor-Diaz buzz reminds us of these classic trilogies

— -- The superstitious belief that bad things tend to happen in threes doesn't seem to hold water in the sporting world.

That thought became evident again this week with the clamoring for a third UFC fight between Conor McGregor and Nate Diaz, almost from the moment McGregor's arm was raised as the victor in their five-round welterweight rematch Saturday night in Las Vegas.

In fact, some of the best rivalries have been bunched in threes. Let's revisit some of the most memorable trilogies in sports history:

Muhammad Ali vs. Joe Frazier

Ali became the boxing legend he was thanks to a handful of gifted opponents, none more than Frazier, who gave Ali all he could handle in their three meetings in the 1970s.

I. The first on March 8, 1971, was dubbed "The Fight of the Century" because it was the first title bout between undefeated heavyweights. Frazier held both belts entering the ring at Madison Square Garden in New York and gradually wore down Ali, even knocking him to the canvas in the 15th round before winning a unanimous decision. Still, Frazier would spend a month recuperating in a hospital afterward.

II. Frazier lost the title two years later to George Foreman, so when he and Ali clashed inside Madison Square Garden for a second time on Jan. 28, 1974, no major belts were on the line. The build-up for the fight was intense, however. Ali and Frazier became physical on the set of "Wide World of Sports," resulting in fines for both, but the actual fight was the least entertaining of the three, with Ali winning a narrow 12-round unanimous decision.

III. Ali and Frazier would clash once more in the Philippines on Oct. 1, 1975, a fight that would later become known as the "Thrilla in Manila" and go down as one of the greatest bouts in boxing history. With the heavyweight title back on the line because Ali had beaten Foreman, the pair went back and forth for 12 rounds before two big rights from Ali midway through the 13th sent Frazier backpedaling. Ali continued the assault in the 14th, prompting Frazier's cornerman, Eddie Futch, to throw in the towel.

Sugar Ray Leonard vs. Roberto Duran

This landmark trilogy featured Leonard's first professional loss and last career victory. And in between, Duran provided one of the most indelible moments in boxing history with two words in Spanish that cross all language barriers: No mas.

I. Four years after Leonard won an Olympic gold medal in Montreal, he returned to the city on June 20, 1980, to take on the rugged Panamanian slugger. Duran was 71-1 entering the WBC welterweight title bout, amassing most of those wins in the lightweight division, while Leonard was 27-0 and five years younger at 24. Leonard elected to fight toe-to-toe with Duran at the start of the 15-round bout and paid a hefty price before briefly returning to his elusive style. The last three rounds went back to a slugfest, and Duran managed to edge Leonard on all three judges' scorecards for what many believe was the biggest victory of his career.

II. The rematch came five months later at the Superdome in New Orleans, and Leonard took advantage of his superior hand speed and quickness to flummox Duran, who eventually turned his back on Leonard near the end of the eighth round and quit, uttering the now-famous line, " No mas."

III. Duran's reputation took a big hit as a result of that move, especially in his home country of Panama. Nine years passed before Duran got another shot at Leonard. By then, Duran was 38 years old and no match for the more spry Leonard, who retained his super middleweight title with a 12-round unanimous decision in Las Vegas.

Affirmed vs. Alydar

Horse racing's Triple Crown of 1978 remains the most hotly contested two-horse rivalry in the sport's history, as chestnut colts Affirmed and Alydar went head-to-head in the Kentucky Derby, Preakness Stakes and Belmont Stakes. Affirmed, ridden by Steve Cauthen, won all three times and was the last horse to win the Triple Crown until American Pharoah in 2015. Alydar, with Jorge Velasquez up, finished second in each of three marquee races, the only horse ever to do so.

I. Alydar was a slight favorite as the horses were locked in the gate for the Kentucky Derby, but his patented late move began too late and he finished 1? lengths behind Affirmed.

II. When they returned for the Preakness two weeks later, Affirmed emerged as the favorite and didn't disappoint, taking the lead at the quarter-pole and holding off Alydar by a neck, 7? lengths ahead of the third-place finisher.

III. Three weeks later, the duo was back on the track in Elmont, New York, and this matchup proved the most exciting. The horses raced side by side over the last third of the 1?-mile Belmont before Affirmed outbobbed Alydar at the finish line.

Larry Bird vs. Magic Johnson

Bird and Johnson combined to reach 14 NBA Finals in their nearly parallel careers, but the Hall of Famers faced off only three times in a championship series.

I. The first time was in 1984, which marked Bird's second trip to the Finals with the Boston Celtics and Johnson's fourth with the Los Angeles Lakers. The series went seven games with the Celtics prevailing and Bird winning MVP honors after averaging 27.4 points and 14 rebounds.

II. They locked up again in 1985, and the Lakers turned the tables by winning their third title of the decade with a six-game victory, finishing off the Celtics in Boston.

III. Bird and Johnson led their teams back to the Finals in 1987, and the Lakers again prevailed in six games, boosted by Johnson's game-winning junior sky hook in the final seconds of Game 4. Johnson and the Lakers defended their title against the Detroit Pistons the following season, but Bird didn't reach another Finals.

Roger Federer vs. Rafael Nadal

Federer and Nadal have gone head-to-head 34 times in their storied careers, but only thrice on grass. Those thrilling encounters occurred in the Wimbledon men's final over three successive years and required a combined 14 sets.

I. The first meeting came in 2006, when the 20-year-old Nadal entered the championship match having won six of his previous seven meetings against Federer, but the Spaniard couldn't close out several opportunities and fell in four sets, handing Federer his fourth straight Wimbledon title.

II. The pair met again the following summer as the top two seeds at the All England Club, and Nadal pushed Federer to five sets, the first time they went the distance against each other in a Grand Slam final. Federer drew the line with a 6-2 win in the final set to win his record-tying fifth straight Wimbledon title.

III. Nadal broke through the following year in their most anticipated and epic meeting on grass, a five-set thriller that set a record for the longest Wimbledon final at 4 hours, 48 minutes. Nadal also ended Federer's Open-era record 65-match winning streak on grass.

Dallas Cowboys vs. San Francisco 49ers

The Cowboys and 49ers met in the first two NFC Championship Games in 1970 and '71, but it was the three straight years they collided in the title game during the 1990s that put their rivalry on par with some of the greatest in sports.

I. Just three years before the first of those meetings, the Cowboys had finished 1-15, but their 30-20 win in the 1993 NFC Championship Game propelled America's team to its first Super Bowl since the 1978 season.

II. The Cowboys followed the same script the next season behind quarterback Troy Aikman and running back Emmitt Smith, beating the 49ers in the NFC title game and then knocking off the Buffalo Bills in the Super Bowl for the second consecutive year.

III. Jimmy Johnson departed as head coach of the Cowboys after the 1994 season, and that change seemed to give the 49ers the edge they needed in the 1995 NFC Championship Game. They surged to a 21-0 first-quarter lead before winning 38-28 and denying Dallas a chance at a record three straight Super Bowl wins. Like the Cowboys the previous two seasons, the 49ers went on to win the Super Bowl.

Pittsburgh Steelers vs. Oakland Raiders

The matchup was just in its infancy and the quality of play was hardly impeccable, but during the three straight years the Steelers and Raiders met in the AFC Championship Game, a rivalry was born.

I. The teams combined for 12 turnovers and Raiders quarterback Ken Stabler completed only 18 of 42 passes in the 1974 AFC title game, a 24-13 win by the Steelers that propelled them to their first Super Bowl victory.

II. Pittsburgh might have played even worse the following year, committing eight turnovers in 16-degree weather before holding on a for a 16-10 win. Steelers wide receiver Lynn Swann left the game because of a concussion caused by a vicious hit by Oakland safety George Atkinson. It was the Raiders' sixth straight loss in an AFC title game.

III. Oakland ended that skid and prevented the Steelers from chasing a third consecutive Super Bowl ring by winning the 1976 championship game game 24-7. Coach John Madden's Raiders followed in Pittsburgh's path from the previous two seasons and won their first Super Bowl two weeks later.

Randy Couture vs. Chuck Liddell

In a sport known for multiple rematches, Couture-Liddell is remembered as one of the first great MMA trilogies. They tangled in Las Vegas three times for the UFC light heavyweight championship, and all three fights ended by knockout.

I. The first took place June 6, 2003, at UFC 43. Couture dropped down from the heavyweight division to take on Liddell for the interim light heavyweight belt that became available when Tito Ortiz was locked in a contract dispute with the UFC. Despite entering as a heavy underdog and just weeks shy of his 40th birthday, Couture forced a stoppage by landing a flurry of punches midway through the third round, becoming the first MMA fighter to win belts in two weight classes.

II. Couture still held the light heavyweight title when he was matched against Liddell at UFC 52 on April 16, 2005, an event that set records at the time for live gate and pay-per-view purchases. Angered after he was poked in the eye in the opening round, Couture abandoned his game plan and charged at Liddell, who knocked him out to become the new light heavyweight champion.

III. The pair would clash one more time 10 months later at UFC 57, and the event would again shatter records for attendance and pay-per-view buys. Couture made another costly mistake and Liddell capitalized much the same way he did in their second fight, winning by second-round knockout and sending Couture into retirement.

Arnold Palmer vs. Jack Nicklaus

Palmer-Nicklaus is still considered golf's greatest rivalry, a competition that peaked at the Masters from 1964 to '66. Nicklaus had won his first Masters in 1963, but Palmer hadn't challenged that year and finished tied for ninth.

I. Palmer, at age 34, became the first four-time Masters champion when he beat the 24-year-old Nicklaus by six strokes at the 1964 tournament, a bit of a payback for Palmer after Nicklaus defeated him by three strokes two years earlier at the U.S. Open for his first professional win.

II. Nicklaus turned the tables on Palmer and everyone else in the field the following spring, shooting a tournament-record 17-under par -- a mark that stood until Tiger Woods shot 18-under in 1997 -- and winning by nine strokes over the second-place Palmer.

III. The Golden Bear continued to steal the Augusta spotlight from Palmer, winning the 1966 tournament after an 18-hole playoff. Palmer missed the three-man playoff by two strokes and finished in a tie for fourth. Nicklaus would go on to win the tournament three more times for a total of six green jackets, a record that still stands.

New York Yankees vs. Boston Red Sox

Two of the most storied franchises in the baseball have met three times for the right to play in the World Series, all in a six-season span, and each of those American League Championship Series?matchups was more legendary than the last.

I. In the first postseason meeting between the teams, the Yankees had too much pitching and needed only five games to beat the Red Sox in the 1999 ALCS before marching on to secure the second of three straight World Series titles. That series was just a warm-up for the next two.

II. They met in the ALCS again in 2003, and this time the Red Sox pushed the series to seven games, reaching the cusp of their first World Series berth since 1986. But Yankees third baseman Aaron Boone hit the first pitch in the bottom of the 11th inning for a walk-off home run, sending New York to the Fall Classic for a third straight season.

III. The Red Sox didn't sulk for long, earning another spot in the ALCS the following year. They proceeded to make history against the Yankees by becoming the only MLB team to bounce back from a 3-0 deficit and win a seven-game series. Boston's rally included extra-inning wins in Games 4 and 5 and Curt Schilling's bloody sock victory in Game 6. The Red Sox didn't let that comeback go to waste, sweeping the St. Louis Cardinals for their first World Series title since 1918.