Ryder Cup: Europe captain Luke Donald gives his opinion on whether US fans crossed the line

European Ryder Cup captain Luke Donald appeared to indicate some United States fans crossed the line during the second day of the matches at Bethpage Black. 

A dominant Europe moved into a commanding seven-point lead ahead of the Sunday singles. 

But the second day of the 45th edition of the contest in New York saw several of his players targeted by an increasingly volatile crowd as the day wore on. 

Rory McIlroy, who has been public enemy number one all week, blew kisses to hecklers on the first tee this morning. 

But he later swore at a group of American fans, telling them to "shut the f--- up" as he lined up his approach into the 16th hole during his foursomes match with Tommy Fleetwood against Collin Morikawa and Harris English. 

McIlroy and Fleetwood ended up defeating the American duo for a second time in 48 hours as Europe moved into a comfortable 8½ - 3½ lead. 

But the abuse continued into the afternoon, with McIlroy and his playing partner Shane Lowry on the receiving end of several unsavoury comments about their personal lives. 

Donald took a diplomatic point of view when he spoke to reporters late on Saturday evening. 

"It was loud," Donald said. "It was raucous. What I consider crossing the line is personal insults and making sounds when they are trying to hit on their backswings or very close to when they are trying to go into their routines. 

"That did happen a little bit. It's happened at other Ryder Cups, too. It's something we prepared for, and I can see, I think, how well they have dealt with it."

For his part, US captain Keegan Bradley acknowledged the fans were passionate. 

But he stopped short of saying whether a line was crossed. The 39-year-old skipper said, from what he heard, that the European fans behaved "pretty violently" two years ago in Rome. 

How did Rory McIlroy react?

McIlroy told reporters it wasn't up to him to decide whether a line was crossed. 

"I don't mind them having a go at us," he said. "That's to be expected. That's what an away Ryder Cup is. 

"Whenever they are still doing it while you are over the ball and trying to hit your shot, that's the tough thing. In between shots, say whatever you want to me. That's totally fine.

"But just give us the respect to let us hit shots, and give us the same chance that the Americans have."

Lowry said: "Look, we knew what we were going to get coming here. It was a very tough day. Being out with Rory doesn't make it any easier. I think he's getting the brunt of it.

"But yeah, look, I think we dealt with it very well. You know, I said at the start of the week, I don't know what way I'm going to deal with it but I'm going to be myself and I was myself out there today and thankfully that worked."