Ricky Barnes made light of the difficult conditions at the rain-hit US Open at Bethpage Black to lead at the halfway stage.
Barnes set the 36-hole tournament scoring record, an eight-under-par 132, after a five-birdie 65 in the second round on Saturday.
Barnes, the 2002 US Amateur champion, is one shot ahead of overnight leader Lucas Glover, who posted a six-under-par 64.
A further shot behind is first-round leader Mike Weir, who shot a 70 to add to his opening 64.
Japan's Azuma Yano shot a 65 to get to three under alongside former Open champion David Duval, who added a 70 to his opening 67, and Peter Hanson of Sweden, who recorded a 71.
Lee Westwood hit an impressive 66 to finish on two under after two rounds.
Defending champion Tiger Woods shot a one under par 69 to make the cut by finishing three over.
Northern Ireland's Rory McIlroy hit a 70 to go to two over, whilst Open and US PGA champion Padraig Harrington hit another six over 76 to finish twelve over.
England's Justin Rose finished his second round at eight over after a 75, whilst Darren Clarke of Northern Ireland shot a 76 to slump to ten-over.