Jason Day survived a rollercoaster final round to complete a wire-to-wire victory in the Arnold Palmer Invitational and move above Rory McIlroy to second in the world rankings.
Day carded five birdies and three bogeys in a closing 70 at Bay Hill to finish 17 under par, a shot ahead of American Kevin Chappell.
Sweden's Henrik Stenson, who has now finished third, second, fifth and eighth in his last four appearances in the event, was two shots further back alongside Troy Merritt, who surged into a share of the lead with five birdies in a row from the 10th, only to double-bogey the 18th.
Day took a two-shot lead into the final round and edged further ahead by chipping in for birdie on the second after a poor tee shot came up well short of the green, only to bogey the next two holes and fall into a tie with Chappell, who had birdied the third.
A birdie on the fifth took Day back in front but Chappell, who was playing in the penultimate group, two-putted the par-five sixth for birdie and then saw Day bogey the same hole after pulling his approach into the water.
Chappell, who is yet to win on the PGA Tour, briefly moved two clear with a birdie on the eighth, but promptly bogeyed the ninth before Day's superb approach to the same hole left him a tap-in birdie.
Stenson made it a three-way tie for the lead with a birdie on the 10th but would go on to bogey the 14th and 16th, while Chappell moved back into the lead thanks to birdies on the 13th and 16th.
However, Chappell dropped a shot on the 18th to open the door for the chasing pack and Day birdied the 17th from 12 feet before saving par from a greenside bunker on the last to claim his eighth PGA Tour title and a sixth in just over 13 months.
Rory McIlroy carded two eagles and five birdies in a closing 65 to finish six under par at Bay Hill, but a double bogey on the 14th was his sixth of the week and his most ever in a PGA Tour event.
The four-time major winner was never in contention for a first win of the season after shooting 75 on the first day and again in the third round, but could take the positives from a 67 on Friday and Sunday's score, which he completed by holing from 60 feet for birdie on the 18th.
Day admitted he had not been at his best during a front nine of 36, but told Sky Sports: "Having a two-shot lead and winning wire-to-wire was not easy. This is a really rewarding win for me.
"To be able to get in the house and make the par on the last where I needed to was very satisfying. There was not one shot on the golf course I hit today where I felt comfortable. I tried to be as deliberate as possible and it worked out on the back side for me.
"I was really nervous over that putt (on 18) after being out of contention for a while and being able to get back into it and knowing that I won wire-to-wire is really special.
"I was all out of sorts on the front side but I kept saying to myself over and over again you are not out of it, be patient, you will find some opening and once you do make sure you take it, and 17 was it."
A disappointed Chappell was left to rue bogeys on the ninth and 18th in his closing 69 and added: "I really felt like I handled myself well and hit some good shots under the circumstances.
"You are going to hit some bad shots and I would love to have nine and 18 back, but that's hindsight and we don't get that. This is going to motivate me to be that close and I am really looking forward to getting back into it in Houston."
