Nowitzki and Ellis were each 4-of-14 from the floor and finished with 11 points, which isn't close to being good enough to beat the team that finished with the NBA's best record.
San Antonio 90, Dallas 85.
It's hard to believe the Mavs led 81-71 with 7:45 left after Brandan Wright's dunk and subsequent foul shot following yet another successful pick-and-roll with Harris.
But then they missed 12 consecutive shots, including four by Dirk. The Mavs didn't score another basket until Harris' layup as time expired.
"I thought Dirk had some good looks and there were some that were heavily contested,"Mavs coach Rick Carlisle said. "It's a long series. The shot-making is going to be up and down a little bit, even if you're one of the 10 greatest scorers in the history of the game."
That was never more apparent than when Nowitzki snatched an offensive rebound after Ellis missed a jumper with the score tied 81-81. He flipped the ball toward the basket and the 2-foot shot rimmed out with 3:32 left.
Nowitzki may be 35, but he remains the epicenter of the Mavs' offense. He averaged 21.7 points this season, good for 13th in the NBA. He shot 49.7 percent from the field, 39.8 on 3-point attempts and 89.9 from the free throw line.
He's still the Mavs' best player, even though owner Mark Cuban and general manager and president of basketball operations Donnie Nelson have unsuccessfully tried to take that title away from him the past couple of seasons.
Until they do, this remains Dirk's team, and his ability to score is paramount to the Mavs winning. He never found a rhythm against the Spurs.
He missed five of six shots in the first quarter and finished the first half with just five points. We've seen Nowitzki have poor-shooting first halves at other points this season.
When it happens, he usually makes a concerted effort to start well in the second half -- even if he has to attack the basket and get to the free throw line just to see the ball go through the basket.
Well, it never happened against San Antonio. You know what, it's OK to give the Spurs some credit for Nowitzki's awful day.
Tiago Splitter, the 6-foot-11 center, did a good job of staying in Nowitzki's personal space, where his long arms make it difficult for the Mavs star to shoot over him.
As a team, the Spurs also do an outstanding job of chasing Nowitzki off the 3-point line and eliminating the trailing 3-point shot from beyond the top of the key from his usual repertoire of shots.
Dirk missed his only 3-point attempt against the Spurs on Sunday. When the teams played April 10, he didn't even attempt a 3-point shot, the only time this season that occurred.
He has made only one of six 3-point attempts in 128 minutes against San Antonio this season.
"They're not necessarily unbelievably athletic and long, but they're smart," Nowitzki said. "What they want to do defensively is take you out of your comfort zone.
"If you like one move, they won't let you get that one move. They usually force you to do something else. They force you to do a 'B' move, not your most comfortable move."
Still, the Mavs had an opportunity to win the game against an opponent that has now beaten them 10 consecutive times.
Dirk has had games of 25 and 22 points against the Spurs this season. The Mavs didn't win those game, but the odds of winning without a strong performance from Dirk are remote.
"I had some decent looks," Nowitzki said. "I just have to shoot better."
He must, or this will be the Mavs' only trip to San Antonio this postseason.