What sets Tiger Woods apart is the willpower with which he finds a way, even when he isn’t playing well. In San Diego these last few days, he has taken his most remarkable trait to yet another thrilling level by challenging for the US Open when he can barely walk properly, never mind perform at his peak. No matter what the world No 1 does in tonight’s final round at Torrey Pines, his contribution to the event has been humbling.

Even if he cannot pull off the win that would be well nigh miraculous so soon after his return from knee surgery, the 108th US Open will have revealed more about the game’s greatest player than any of his 13 major triumphs. Woods would have been forgiven had he chosen to skip this most rigorous of physical challenges, and so maintained the air of infallibility with which he intimidates others, but halfway through yesterday's third round, he was sharing second place with Lee Westwood, Miguel Angel Jimenez and Davis Love III, three strokes behind the unlikeliest of leaders, Rocco Mediate.

Woods hauled himself into that position despite a pain with which he has been plagued all week, even if he refuses to admit as much. Good players don’t like excuses, for they are a licence to permit failure. Woods has led us to believe that this knee problem of his, which has kept him out for nine weeks, and denied him a single competitive round since The Masters, is “no big deal”.

Asked when he comes off the course whether he feels any pain, “uh, huh” is the extent of his response. Pressed further, he opens his heart to the world’s media. “It’s a little sore,” he reveals.

However much he tries to play it down, Woods has been hurting, and not just a little. Quite apart from the rustiness he has had to shake off at the beginning of each round — his first six strokes of the tournament amounted to double-bogey — there is no disguising the effect on his knee of physical stress.

His drive from the 18th tee in Thursday’s opening round prompted a grimace that gave the game away. And before his second round, he was spotted limping on the range. But it was during Friday’s play that he let slip the most visual demonstration yet, not only of his pain barrier, but of his determination to play through it. The first at Torrey Pines, Tiger’s 10th that day, was a turning point at this year’s US Open, the juncture at which winning the title on one leg seemed not so outlandish a proposition.

After his wild tee shot ended up on a cart path, he decided against the drop that would leave him behind a tree, with no shot, opting instead to play off the concrete, metal spikes and all. As a whipped eight iron sailed off towards the green, Woods hobbled back to his bag in pain more apparent than any he had experienced all week. There were fears this could be the breakdown he had been refusing to accept, the point at which reality set in for a man who allows himself to be credited with superhuman qualities, but that wasn’t how it worked out. Not in the slightest.

What could have been the signal for a downward spiral was instead a red rag to Tiger, and not just because he holed his 15-footer for birdie. Despite walking gingerly between shots, and growing whispers that he might be on the brink of withdrawal, Woods summoned enough composure not only to keep going, but to put together his best nine-hole stretch in a major for 10 years. Sinking putts from all manner of ridiculous angles, he racked up five straight threes to return home in an astonishing 30 strokes. When the dust settled high on the cliffs above the Pacific, he had signed for a 68 that left him on two under par.

His start to the third round would have been regarded as catastrophic were the entire field not also going backwards on a difficult day at Torrey Pines. After yanking his drive into the left rough, he was too ambitious with his second, and needed two more chips to leave himself with a nine-footer for bogey. He missed. After eight holes, he was still two over for the day.

Phil Mickelson, with whom Woods shared the big stage in that circus of a match on days one and two, gave up all pretence of challenging yesterday. Having started on four over par, he struggled all day to make headway, and eventually played himself out of the tournament in a manner ill becoming of the world No 2. On the par-five 13th, he ran up a nine, not by losing a ball or by thrashing around in the deep rough, but by contriving no fewer than four times to spin his pitch back off the front of the green and down the hill. It was an unedifying spectacle compounded by three putts. By the time he trudged off the final green, where his birdie was was academic, he had taken 76 and slipped to nine over for the tournament.

The fate of the local favourite has been one of many strands to this captivating tournament. The United States Golf Association, so often the brunt of criticism, must be patting itself on the back right now, having endeavoured to make of its showpiece event a more entertaining spectacle than usual. This US Open has been a far cry from the plodding ones of old, in which there was no choice but to play safely up the middle, chop out of the knee-high rough when necessary, but first and foremost, resist all temptation to be imaginative.

Here, there have been eagles, unlikely recoveries from the long stuff, and even the odd putt from 30 yards off the green, as closely-mown areas around the putting surfaces promote a degree of invention. For once, protecting par does not appear to be the USGA’s priority. Statistically, the second round played two shots easier than the first, which is almost unheard of in a tournament that traditionally grows more brutal by the day. Recent changes at Augusta National have led some to describe The Masters as the new US Open. Any more of this, and they’ll be calling the US Open the new Masters, especially if Woods remains high on the leaderboard.