Merion Golf Club has now extracted three pounds of flesh from the field at the U.S. Open, and Phil Mickelson holds the solo lead at 1-under par.

After third-round 70, Mickelson leads by a stroke over Hunter Mahan (69), Charl Schwartzel (69) and Steve Stricker (70) and by two strokes over Justin Rose (71), Luke Donald (71) and Billy Horschel (72).

Rounding out the top 10, Jason Day (68) is three shots behind, Rickie Fowler (67) is four behind and 19-year-old amateur Michael Kim (71) is five off Mickelson’s lead. Tiger Woods struggled to a 76 and is 10 shots off the lead, tied for 31st place.

Mickelson’s round got off to a shaky start with bogies on Nos. 3 and 5, but he made three back-nine birdies before a closing bogey on the par-4 No. 18, which played 530 yards in Saturday’s round and yielded no birdies, with a scoring average close to a full stroke over par.

And so Mickelson, who will turn 43 Sunday, has once again thrust himself into the spotlight of major championship pressure in an event where he has a record five times finished in second place. Mickelson’s four major championships — three Masters and a PGA Championship — have assured his place in golf’s pantheon, but for him to win the trophy whose absence has defined his recent golf résumé would be one of golf’s most triumphant stories of all time. And so it is fitting that the man with seemingly both the most to gain and the most to lose is leading the U.S. Open through 54 holes.

But that is not to say that a Mickelson win is the only great potential scenario that could unfold Sunday. A win for Stricker would be historic as he would be both the oldest man to win a U.S. Open and the oldest first-time major winner. A win by Rose, Mahan or Donald would allow them to shake away “Best Player Without a Major” whispers. Wins by Horschel, Fowler or Day would continue to herald the youth movement evident in professional golf and bring them into company with Rory McIlroy.

McIlroy, paired with Tiger Woods, struggled to a five-over par 75 and will in all likelihood have to wait a few weeks to try for his third major championship victory.

Saturday’s proceedings showed how excellent a U.S. Open site Merion has proved to be. The leader board is stocked with players of all types, showing that no one type of game has a clear advantage at one of the world’s greatest courses.

Two players began the day under par for the tournament, and the course’s enticing middle section brought a few more players under par — into and around the lead — before punishing them with the finishing stretch, which to this point is harder than any other in U.S. Open history. No. 18 alone extracted a double bogey from Luke Donald, a triple bogey from Nicolas Colsaerts (5-over, T11) and five further bogies from the last three threesomes.

Sunday will be another brutal challenge that will, excepting a tie and a Monday playoff, leave all but one player atop the ash heap. No matter who ultimately wins, the remainder of the tournament will reveal an exhausted but all-deserving champion.