Phil Mickelson tees off on the fifth hole during the second round of the U.S. Open golf tournament at Merion Golf Club, Friday, June 14, 2013, in Ardmore, Pa. Jaco Van Zyl, of South Africa, putts on the ninth hole during the second round of the U.S. Open golf tournament at Merion Golf Club, Friday, June 14, 2013, in Ardmore, Pa. (AP) - Five things to look for Saturday in the third round of the U.S. Open: Phil Mickelson has a checkered history in the U.S. Open and, unfortunately for him, not much of it is good. The five-time runner-up has never won the championship, and famously gave away the 2006 title on the last hole. Mickelson birdied the last hole Friday as darkness fell on Merion Golf Club to move back into a tie for the lead with Billy Horschel at 1-under par, and has 36 holes between him and the Open championship he desperately wants. Well, he's the winner of the Zurich Classic this year and a cut-making machine who seems to be coming into his own as a pro. The 26-year-old former Florida Gator showed he can play under pressure at the TPC Louisiana course, where he tied the course record with a 64 and made a 27-footer on the last hole to win. Still, he missed the cut in his only other Open in 2006, and playing under the spotlight on the weekend will be a new experience for him. Yes he can, after a second round of even-par 70 put him within four shots of the lead. Tiger Woods faces a pair of obstacles, though, including an inflamed elbow and the fact he has never won a major after shooting over par over the first two rounds. Even though it's been five full years since he won his last Open, on one leg at Torrey Pines, he's still Tiger Woods, owner of 14 major titles. ONE TOUGH OPEN: The talk coming in was that rain softened venerable Merion so much that players would have their way with the grand old course. So much for talk. Though there are still some groups that have to finish their second rounds, only Mickelson and Horschel are under par in the 156-man field. Players are averaging a whopping 74.69 over the par-70 course, where Ben Hogan won in 1950 and Bobby Jones completed his Grand Slam in 1930. Ian Poulter was the hero of the Ryder Cup for Europe last year and a consistent performer in big events. But he's yet to win a major championship and until he does he will always be listed in the second tier of players. Poulter started this Open with three straight birdies Thursday before faltering, but rebounded in his second round and was even par with four holes left. He should be among the late groups teeing off in the third round, poised to make a run at the lead.