Rory McIlroy has admitted that he found it "tough" to get the job done while watching Tiger Woods surging up the leaderboard.
The Irishman clinched the Honda Classic title at Palm Beach in Florida by carding a closing round 69 to end the championship on 12-under par.
However, it was not plain sailing for the 22-year-old, who scrambled to make par on a few occasions over the back nine.
"It was tough today, especially seeing Tiger make a charge," McIlroy said. "I knew par golf would probably be good enough.
"My short game all week has been very good, and it's what you need on a tough golf course like this.
"To shoot one under in these conditions, when you go into the round with the lead, is very nice. I was just able to get the job done."
McIlroy's win sees him overtake Luke Donald at the top of the world rankings.