Phil Mickelson  regained the lead of the US Open after Luke Donald dropped two shots in his last three holes in the first round of the US Open at Merion. Resuming at four under on the 14th tee after a rain-hit opening day, overnight leader Donald ended with a two-under 68 to slip behind Mickelson (67). Matthew Goggin also ended two under, with Scotland’s Russell Knox and Belgium’s Nicolas Colsaerts one under. Tiger Woods and playing partner Rory McIlroy both carded 73. Woods appeared to be troubled by a left elbow injury on the first day and hinted at it again on Friday. The 14-time major champion resumed at two over and made his par putt on the 11th to start his day but bogeyed the 12th before a birdie on the short 13th and another bogey on 17. “It’s one of those golf courses where there’s some easy holes and there’s some hard holes that follow,” said Woods, who is chasing his first major title for five years. “You got to take care of the easy holes and try and get through the hard ones. “For some reason I left myself quite a few putts (that) were easily makeable and I didn’t make any.” Woods admitted his left arm “didn’t feel very good” on “a few shots” on Thursday. Asked what he felt, he answered: “Pain.” “But it is what it is,” he added. “And you move on and I got to get ready for this next round in a little bit Northern Ireland’s McIlroy, the 2011 champion, dropped to level par when he missed a par putt on the 11th green at the end of Thursday’s play, and slipped further with bogeys on the 15th, 17th and 18th.