Ricky Barnes further staked his claim to a US Open victory as the third round came to its conclusion, but it could have been so much better for the American at Bethpage Black.

As the second major of the year headed for a first 72-hole Monday finish since 1983, Barnes had threatened to set more records after shooting the lowest 36-hole total in US Open history, a 132, on Saturday.

The American, playing his first full year on the PGA Tour in his seventh year as a professional, was going the right way about emulating 2003 Open champion Ben Curtis in making his maiden professional victory at a major.

Barnes, starting the day at eight under with a one-shot lead over fellow American Lucas Glover, moved into a three-shot lead after six holes thanks to a birdie at the second and a long-range eagle putt at the fourth.

The eagle got the 28-year-old to 11 under par, the first man to move into double digits at the US Open since Jim Furyk in the third round at Olympia Fields en route to his victory in 2003.

Despite a bogey at the seventh, Barnes' lead stretched to six shots at the eighth as both Glover and Mike Weir in third place, slipped to four under.

Yet Barnes unravelled a little after turning for home, bogeying the long and difficult par-fours at 10 and 12 as Glover birdied the 10th and 11th.

Barnes rebounded with a birdie at 13th but his three-shot lead over the field at nine under after 14 holes gave his rivals some hope they could reel him in over the final round, which was set to start late on Sunday.

Weir was at two under playing the 16th in a tie for third with David Duval, who birdied the 16th to also join Hunter Mahan, with a 68 and world number two Phil Mickelson, who delighted his big following of fans by sinking a 38-foot birdie putt at the 18th for a 69.

England's Ross Fisher had got to three under after four holes but he stayed in touch with the leaders at two under playing the last.