Fans' venom toward Team Europe's McIlroy? Simply puzzling

— -- CHASKA, Minn. -- Rory McIlroy is a big boxing fan, and he looked as if he had gone 15 rounds late Saturday afternoon as the sun set on Hazeltine National. A raging headache was surpassed only by the rage he carried around with him for 11 riveting hours at the Ryder Cup.

McIlroy threw a few haymakers himself, and the celebratory uppercuts were part of an exhausting day that saw him and Thomas Pieters win two matches for Europe while also fighting the unfortunate battles with those outside the ropes.

The ugliness was outdone only by McIlroy's inspired golf. And when he started to wane toward the end of the day, there was Belgium's long-hitting Pieters to pick him up off the mat.

After a 4 and 2 victory against Phil Mickelson and Rickie Fowler in the morning foursomes, McIlroy and Pieters took it to Dustin Johnson and Brooks Koepka in the afternoon, never trailing, building a 4-up lead and withstanding a late mini-rally to close it out 3 and 1.

The European duo has combined for 3 of Europe's 6? points, while putting up with a good bit of undesirable nonsense from a loud, obnoxious minority of spectators who for some unknown reason have taken out their anxieties on one of golf's nicest and most accomplished players.

"It's a tough environment for us to come play in," said McIlroy, a four-time major winner from Northern Ireland who now lives in Florida. "We expect that. It's the same for the U.S. guys when they come to play in Europe. You have to keep your concentration out there. It's been a long day and sometimes emotions run high."

McIlroy was being diplomatic while trying to carry the European team on his back -- along with Pieters, who is now 3-1 in his first Ryder Cup. If the European galleries have ever gone over the line, it has not been to the extent heard here.

It was more than clear that McIlroy was agitated with the behavior of spectators who went beyond the typical partisan rooting that is common and a part of the Ryder Cup. He was heckled throughout the day, and while a good bit of it was in good fun, it became increasingly nasty as the alcohol flowed and the day became more intense.

After making what was an unlikely birdie at the seventh hole of the afternoon match, McIlroy punctuated his celebration by turning toward Lake Hazeltine and letting out a howl which pierced the murmuring in the crowd. And then it got particularly unpleasant.

As he walked to the 8th tee, a 300-yard journey that becomes a gauntlet as fans scream and yell from a few feet away outside the ropes, at one point, a fan leaned toward McIlroy and screamed an obscenity at him.

For most of the day, McIlroy ignored the taunts. But this was impossible to put aside. McIlroy, seething, immediately stopped and pointed at the fan, called for security and continued a stare down that didn't end until a police officer arrived. McIlroy then headed up the hill to the tee, striped a 3-iron onto the green and he and Pieters won the hole to go 3-up.

"It fueled me a lot," he said. "The more they shouted, the better we played. I hope they shout all day tomorrow."

McIlroy has probably not helped matters. The best way to deal with the unruliness and crudeness is to ignore it, pretend those fans and their comments don't exist, go about the business of making birdies and posting blue on the scoreboard. Easy for you or me to say.

The taunts then got personal. He was serenaded several times with "Sweet Caroline," a reference to his former fianc?e, professional tennis star Caroline Wozniacki. At one point, he mockingly sang along, clapping. All the while, his current fianc?e, Erica Stoll, walked along inside the ropes. Yep, classy.

When his approach shot found the water next to the 16th green -- helping to momentarily extend the match -- the crowd erupted as if the Vikings had just scored a touchdown in the old Metrodome.

There's nothing wrong with such partisan cheering at the Ryder Cup. But why such venom has been directed at McIlroy is beyond puzzling. This is one of the more popular, gracious players when he competes in PGA Tour events. He just won the Tour Championship on Sunday -- and the FedEx Cup's $10-million bonus -- and you'd be hard-pressed to find anyone at the tournament who didn't cheer that victory.

"It's been tough, but you have to keep your focus and concentration at all times and not let it affect you," said McIlroy, who admitted tiring toward the end and was backed up by Pieters, who birdied three of the last five holes. "But, at the same time, when you play a good shot or you win a hole or you hole a putt, you want to let them know that.

"So as much as they are giving it to us, we are trying to give it straight back at them."

The big question now is if McIlroy has anything left. Playing five matches, as he will do at this Ryder Cup along with four of his teammates, is exhausting. He left Hazeltine on Saturday evening in a bit of a daze. There was some great golf, but Pieters -- who won an NCAA title at the University of Illinois in 2012 -- offered support in the end.

That won't be the case in singles on Sunday, when captain Darren Clarke desperately needs McIlroy to help the Europeans overcome a 9? to 6? deficit. McIlroy has never lost in three singles appearances, and now is not the time to start.

McIlroy, who was energized by all of the emotion and adrenaline Friday, might be running out of energy at this point. But don't bet on it. As he said, the negativity has fueled him, and his production of points proves it.

He'll need to punch back for one more day.