Phil Mickelson defied the odds to become the oldest major champion in history as he overcame a nervy back-nine to clinch a memorable two-shot victory at the 103rd PGA Championship.
Mickelson was five shots clear of the field until mistakes at the 12th and 13th offered hope to Brooks Koepka and Louis Oosthuizen, but the left-hander was not to denied his place in the record books as he had his name etched on the Wanamaker Trophy for the second time, and matched the six major hauls of Sir Nick Faldo and Lee Trevino.
The long and punishing Ocean Course at Kiawah Island was tamed by a man just over three weeks shy of his 51st birthday, although he was given a helping hand by some uncharacteristic mistakes from playing partner Koepka, while Irish duo Padraig Harrington and Shane Lowry both closed with 69s and just missed out on a podium finish.
Mickelson made par at only one of the first seven holes, but three bogeys and three birdies – including a trademark chip-in from the sand at the short fifth which set the pulses racing – were enough to keep him at seven under with Koepka dropping three shots at the two par-fives on the front nine.
Koepka looked favourite to collect his third victory in four years when he birdied the first only to go off the beaten track at the long second, where he needed five shots to hit the green before two-putting for a double-bogey seven as Mickelson’s birdie completed a three-shot swing.
The two-time champion blocked out the roars from Mickelson’s unlikely birdie at five to make a good three at the sixth, but he gave that straight back with a bogey on the next after Mickelson chipped to 10 feet and rolled in the putt for his third birdie of the day.
Two solid pars took Mickelson to the turn in 36 and he edged further ahead with another confident putt for birdie at 10 just as Koepka began an ill-timed slide down the leaderboard, dropping three shots in four holes including another six at the par-five 11th.
With Koepka heading in the wrong direction, Oosthuizen suddenly emerged as the biggest threat to the 50-year-old fan favourite, but the South African’s birdie at 12 was swiftly forgotten when he made a mess of the 13th – stabbing back to the fairway after a poor drive before blocking his third into the water.
The resulting double-bogey appeared to pave the way for a Mickelson procession down the stretch, but the pressure of leading a major began to take a toll on the seasoned veteran, who tugged his approach to 13 into the drink and did well to scramble a five, and he was unable to get up and down for par after coming up short with his tee shot to 14.
But Mickelson, who spoke on Saturday night of the need to maintain focus and sharpness, regrouped with a solid par at 15 followed by a priceless birdie at the next, where his mammoth 366-yard drive was the longest of the week on the final par-five.
Koepka, meanwhile, kept his slim hopes alive with birdies at 15 and 16 to leave Mickelson three clear heading to the fearsome 17th, where Oosthuizen made par before narrowly missing out on a three at the last, signing for a 73 and a score of four under par – his fifth major runner-up finish.
Mickelson took the water out of play as he hammered his long-iron over the back of the 17th green, where he was content to take three to get down with Koepka holing a clutch putt for par that kept him two back with just the 72nd hole to play.
The champion-elect was taking nothing for granted when he pushed his drive into the left rough with Koepka nicely placed on the fairway, but Mickelson had one last magical shot in his locker, knocking his approach to the heart of the green to make the victory stroll a lot less stressful.
Surrounded by thousands of fans in scenes similar to Tiger Woods winning the Tour Championship in 2018, Mickelson kept his composure in check while Koepka closed out a disappointing 74, lagging up to the hole-side and tapping in for his moment in history – a 73 enough for a winning score of six under par.
Harrington, who will join Mickelson among the senior ranks when he turns 50 in August, eagled the second and chipped in for birdie at the 14th on his way to his best finish in a major since 2012, and his best result in the PGA since his victory at Oakland Hills in 2008.
The European Ryder Cup captain shared fourth place with Lowry on two under par after the Open champion missed a great chance from six feet at the last for a 68, while the charismatic Harry Higgs fired a creditable 70 to record his career-best finish in a major.
Paul Casey made it a four-way tie for fourth with a five-birdie 71, with Justin Rose (67), defending champion Collin Morikawa (68) and Jon Rahm (68) also forcing their way into the top 10 with Abraham Ancer, whose 65 was the low round of the championship.