American Jimmy Walker survived a marathon final day and held off the determined challenge of defending champion Jason Day to win his first major title in the weather-affected US PGA Championship.
Walker carded a closing 67 at Baltusrol to finish 14 under par, one shot ahead of Day after the world number one stunningly eagled the final hole to pile on the pressure.
A par was still good enough for Walker to become the eighth wire-to-wire winner of the US PGA - and the first since Phil Mickelson at the same venue in 2005 - and the 37-year-old held his nerve after pitching to 30 feet from right of the green.
Walker's win booked a second consecutive appearance in the Ryder Cup and completed a clean sweep of 2016 majors by first-time winners after Danny Willett (Masters), Dustin Johnson (US Open) and Henrik Stenson (Open Championship).
Stenson was in contention for back-to-back majors until a double bogey on the 15th ended his chances, the 40-year-old Swede having to settle for a tie for seventh with playing partner Martin Kaymer, who eagled the last in a closing 66.
One of 10 players forced to play 36 holes on Sunday after the previous day's thunderstorms, Walker started his third round at 7.40am local time and carded a 68 to take a one-shot lead into the final round.
A run of nine straight pars was enough to keep Walker's nose in front before the world number 48 - the lowest ranked major winner since world number 108 Keegan Bradley won the 2011 US PGA - doubled his lead in brilliant fashion by holing out from a bunker on the 10th.
Day, who was looking to become the only player after Tiger Woods to win back-to-back titles since the US PGA became a strokeplay event in 1958, had bogeyed the first and third but bounced back with birdies on the fifth and ninth.
The 28-year-old also immediately answered Walker's bunker shot by making a birdie on the 11th, only for Walker to hole from 30 feet on the same hole 10 minutes later.
Day was unable to pick up any further shots before hitting a superb approach to within 15 feet of the hole on the 18th, prompting a roar from the crowd which forced Walker to back off his birdie putt on 17 before crucially holing from eight feet for a three-shot lead.
Padraig Harrington was the only Irish golfer to make the cut and finishes in a tie for 13th after posting a final round 68 to get to six under.