Rory McIlroy became the sixth-ever player to achieve the career grand slam by winning the 2026 Masters.

But Phil Mickelson may feel strongly that he should have achieved it first, and he was one hole away from doing exactly that.

Mickelson, a six-time major winner, has won almost everything there is to win in the game. He’s a three-time Masters winner, two-time PGA Championship winner, and won The Open Championship in 2013.

But the word “almost” is a painful one in Mickelson’s case. He has been a runner-up at the U.S. Open a record six times, and it’s the only major missing in his trophy cabinet. He should have won it in 2006, but he collapsed on the final hole.

Phil Mickelson’s 2006 collapse cost him the career grand slam

The 2006 U.S. Open at Winged Foot Golf Club was a brutally tough test for the entire field. Mickelson entered the final day five over par, but was still tied for the lead.

Despite a difficult start to his Sunday round, featuring three bogeys in the first five holes, Mickelson steadied the ship down the stretch and led by one going into the 18th. Also in contention and just one shot behind him was Australian Geoff Ogilvy, going for his first major championship win.

Ogilvy parred the final four holes, an impressive achievement around this golf course, meaning Mickelson needed a par to win the tournament.

But instead of pulling out a 3-wood or iron off the tee, Mickelson went driver. It was a decision he would immediately rue. His drive sliced left and smashed into the hospitality tent.

He could then have chipped back onto the fairway and taken a bogey to force a playoff. But Mickelson stayed aggressive. After a long wait, he went for the green, hitting a tree which stopped his ball just 25 yards in front.