Three years ago, on Shinnecock Hills’ steeply tilted 13th green, 47-year-old Phil Mickelson batted a wayward third-round US Open putt back up the slope without waiting for the previous stroke to stop rolling.

It was a bizarre incident, likely born of frustration at the arrangement of the course, but seemingly signalled an end to Mickelson’s serious tilts at winning big championships.

Only Julius Boros had won a major championship past his 48th birthday and Mickelson, on that day, put up the white flag.

Later in 2018 Mickelson flew with his Ryder Cup teammates into Paris and a sound beating by the Europeans. Few of the Americans played well, but one abiding memory was of Mickelson dumping an iron into the pond to the right of the not particularly difficult par-3 16th to lose to Francesco Molinari in the final day’s singles matches. It was a shot seemingly destined to be his last in the Ryder Cup.

Since he turned 50, Mickelson has won on the senior tour, but offered little in the way of encouraging play on the main tour.

No one even considered him a possible contender on a course earning a reputation as Pete Dye’s most difficult.

But he’d lost weight – using the best diet ever devised of eating less – and advanced his swing speed by enough to keep him up with the modern bombers (reaching 15th in driving distance this week).

And with 30 years of tour experience, he’s clearly learned how to get himself around a golf course – especially one quite different from the week-to-week norm on the PGA Tour.

Brooks Koepka was the most likely winner when play started today and, after a birdie on the first, a sure bet. Instead, he made a seven at the par-5 second and followed up with a pair of sixes at the next two long holes.

It’s hard – at best – to win a tournament dropping four shots on par fives. And, as far as these guys drive, it’s more akin to dropping five or six shots to the field than four. Mickelson, in contrast, played the same three holes in four, four and five – six shots better.

Mickelson and Ernie Els were schoolboy rivals and for the longest time the South African had the best of it, winning three majors before Mickelson won his first.

Els also won a lot more around the world, proving himself on courses as varied as Oakmont, Royal Melbourne, Muirfield and Wentworth.

Both, though, would probably have won a lot more if not for Tiger Woods who was just … well … better. Which is saying a lot, because Els and Mickelson were easily the best players, Woods aside, of their generation. Someone also pointed out that both are much wealthier than they might have been because of Tiger, such was the money he brought to the game.

Now Mickelson will be back in the Ryder Cup – it is, after all, a commercial vehicle and there is no chance Steve Stricker isn’t going to pick the crowd favourite.

He’s earned five more years at the US Open, just in the nick of time as his exemptions were clean out and he was relying on the largesse of the USGA to offer him an invitation.

Six times he has been second in his national championship, two more than another former great 50-year-old player, Sam Snead. Peter Thomson would be quick to point out the advantages of a long swing as one enters the senior years.

It’s all but impossible to believe neither Snead nor Mickelson picked off one US Open between them.

Surely it’s too late.

But after this, maybe not.