Masters champion and world No.2 Jordan Spieth and fellow young gun Patrick Reed made their moves at the US Open, surging to a tie for the lead after the second round at Chambers Bay.
Spieth put together a three-under-67 on Saturday to move to five-under par for the championship, joining Reed (69) at the top of the leaderboard.
The Ryder Cup teammates lead by a stroke from Dustin Johnson (71) and South African Branden Grace (67) who sit four under while Joost Luiten (69), Tony Finau (68), Daniel Summerhays (67) and Ben Martin (70) share fifth at three under.
A major story of the afternoon came from Jason Day, as the Queenslander put a huge scare through the tournament when he collapsed on his final hole with a bout of benign positional vertigo.
He was able to finish off his round with a bogey after receiving treatment on course, signing for an even par 70 to be at two under in a tie for ninth.