Former champion Phil Mickelson went clear at the top of the leaderboard at the British Open on Thursday after a stunning eight-under-par first round of 63 at Royal Troon. Instead Mickelson becomes only the ninth player to score a round of 63 at the Open, with the last being Rory McIlroy in 2010. Left-hander Mickelson's effort was, though, the lowest round at Troon, beating the 64 of Greg Norman in 1989 and Tiger Woods in 1997.
