Rory McIlroy and Jason Day appeared certain to miss the cut at the U.S. Open after ending their second rounds on five and 10 over par respectively.
Playing together alongside Justin Rose at Erin Hills, world number two McIlroy and the third-ranked Day each struggled on Thursday as they shot 78 and 79.
McIlroy at least improved his position in round two, almost holing his tee shot at his final hole - the par-three ninth - as he completed a 71 with four late birdies.
However, he was still well outside the top 100 at five over, with only the top 60 and ties making the weekend. And Day was even worse off, a 75 leaving him tied for 150th.
Rose was also vulnerable at two over, a score that left him one shot outside the cut line with Friday's later starters still to tee off.
McIlroy - the U.S. Open champion in 2011 - made his return from injury this week and admitted to feeling 'rusty' following his first round.
World number one Dustin Johnson was facing a battle of his own to make the cut. He was due out at 2:20pm local time, having begun the tournament with a three-over 75.
As McIlroy and Day finished their second rounds, Paul Casey and Rickie Fowler held the lead at seven under.