Emerging golf star Lucas Herbert has upstaged former world No.1s and major winners Adam Scott and Jason Day to finish top Australian at the US Open in New York.

Australians Adam Scott, Jason Day, Cameron Smith and Lucas Herbert have all crashed out of US Open contention during the third round at Winged Foot in New York.

Australia's nine-strong US Open contingent has been slashed by more than half after a brutal second round at Winged Foot in New York.

Justin Thomas holds a one-shot lead after an opening round of the US Open where Phil Mickelson and Tiger Woods struggled at Winged Foot.