England’s Ian Poulter and South African Charl Schwartzel set the pace as the first round of the US Open Championship resumed after a three and a half hour storm delay at Merion.
Less than two hours' play had been completed the horn reverberated at 8.36am to suspend play as a large storm drew near, and the subsequent wind and rain kept the players off the course until 12.10pm.
Ryder Cup hero Poulter had been at the top of the leaderboard after opening with three straight birdies after starting at the 11th, but upon resuming did well to escape with just a bogey on the 14th after hitting his drive into heavy rough.
That allowed Schwartzel to take the lead with a hat-trick of gains from the 13th - like Poulter he started at the 11th - but the Englishman responded with a brilliant curling seven footer at the 15th which snuck in the side door for birdie.
Schwartzel’s compatriot Tim Clark was third on two under through seven, with the afternoon starters unlikely to complete their opening rounds before dark.
Any fears that Merion would be too easy for modern players and equipment, especially with soft conditions, were proving unfounded, with level par currently good enough for a share of ninth place.
Mickelson had briefly moved into the outright lead with a birdie on the seventh, but was joined on two under by veteran compatriot Jerry Kelly, the 46 year old having carded three birdies and just one bogey in his first 15 holes.
Belgium's Nicolas Colsaerts was one behind with just one hole to play, the Ryder Cup star recovering from three bogeys in five holes with birdies at the seventh and eighth.