Second-round leader Rory McIlroy faltered on day three of the St Jude Classic in Memphis as Nick O'Hern, Davis Love III and John Merrick moved to the head of the leaderboard on six under.
McIlroy was a shot clear of the pack after 36 holes but lost ground after signing for a two-over-par 72. While the Northern Irishman had a day to forget, Australian O'Hern leapt 11 places to the summit after shooting a second consecutive 67.
He made his move after shooting level-par on the front nine, collecting four birdies and a single bogey after the turn.
Love joined him on six under with his third 68 in as many days - built around four birdies and two bogeys - and Merrick was one under for the day after picking up shots at the 16th and 17th to end his round on a high.
McIlroy, who will defend his US Open title in San Francisco next week, struggled to put a decent sequence together all day. As if to indicate that inconsistency from the off his first three holes yielded par, bogey and birdie.
He went on to pick up strokes at the fifth, ninth, 10th, 13th and 15th holes but prevented complete meltdown by by birdying on three further occasions - including the final green.
McIlrory is one of six players one shot off the leading trio, joined by Dustin Johnson, Robert Allenby, Kevin Kisner, Chad Campbell and Kevin Stadler.
Johnson and Allenby were the biggest movers in that group, both up 14 places after matching 67s.
JB Holmes, second overnight, is two off the lead after shooting two over par on the day, with nine more players one more back.
Two of those - Sweden's Frederick Jacobsen and American Roberto Castro - shared the best score of the day, 66.