American Patrick Reed has vowed to "block out all the noise" surrounding him following his victory in the WGC-Mexico Championship.

Reed carded a final round of 67 at Chapultepec Golf Club to finish 18 under par, a shot ahead of Ryder Cup team-mate Bryson DeChambeau, and claim his eighth PGA Tour title.

The 29-year-old's performance was all the more impressive given that it came in a week when his conduct on the course came under renewed scrutiny, initially regarding the two-shot penalty he received during the Hero World Challenge in December.

Reed said he had not intended to improve his lie by removing sand behind his ball during two practice swings, but that explanation cut little ice with many players, including former world number one Brooks Koepka.

In an interview with Sirius/XM during a promotional tour for the PGA Championship, Koepka said: "I don't know what he was doing, building sand castles in the sand, but you know where your club is.

"If you look at the video, he grazes the sand twice, and then he still chops down on it. If you play the game, you understand the rules."

Those comments were swiftly followed by the release of a No Laying Up podcast with former CBS commentator Peter Kostis, who said he had  witnessed Reed improving his line of play in the rough.

"I've seen Patrick Reed improve his lie up close and personal four times now," Kostis said.

Asked in his post-round press conference on Sunday if he felt he had something to prove, Reed said: "I felt like I had something to prove to myself coming into this week because I feel like I've been playing some really solid golf and just haven't quite gotten over that hump to get the W (win).

"But then coming into this week, I knew we were in a good pattern and I knew all I needed to do was continue to try to improve on my golf game, but at the same time just block out all the noise, no matter what it was.

"I feel like I've been able to do that really well throughout my career, and growing up I've always been able to kind of, when I get inside the ropes around the golf course, just focus on what I need to do, and that's play golf."

Asked if he feels like the world is against him, Reed added: "I'm used to it.

"Honestly, it's one of those things that at the end of the day, all I can control is me and what I do on and off the golf course.

"And if I feel like I'm improving each day on and off the golf course and setting a good example for the next generation coming up, the children, as well as my own children, then that's all I can do, and I feel like I've been doing a good job of that, and I feel like I've been growing as a person and as a golfer, and that's all I can really do."

World number one McIlroy started the round four shots off the pace and made an early charge with birdies at the first, third and sixth, but bogeyed the 12th and had to settle for a closing 68 and fifth place.