Tiger Woods found himself in unfamiliar territory as he lost the lead and almost dropped out of contention after the second round of the Arnold Palmer Invitational at Bay Hill last night.

Rocco Mediate fired a five-under-par 65 to surge past Woods and the rest of the field and take a three-stroke lead going into the weekend.

Playing in his fourth event of the year Woods had carded a 64, his best round of the season, on Thursday to grab a share of the first-round lead. But the world's top-ranked player stumbled to a three-over par 73 to fall six shots behind Mediate, who leads the way with a nine-under score of 131.

A four-time winner of this event, Woods recorded two birdies and three bogeys to go with a stunning double-bogey at the par-five fifth hole.

Mediate followed up his opening-round 66 with another crisp effort in producing six birdies and just one bogey.

Paul Casey, who began the day tied for the lead, shot an even-par 70 and is level with John Rollins on six-under. Rollins matched Mediate's effort with a bogey-free 65.

Sergio Garcia is in a group a shot behind Casey and Rollins that features Shaun Micheel, Ben Curtis, Stephen Ames and first-round co-leader Vaughn Taylor. Retief Goosen joined Woods in a group of six players at three under.

Darren Clarke's poor run of form continued in Florida as he carded a second round of 77 to miss another cut. Clarke, who finished way down the field on 10-over, will now miss next weekend's CA Championship as his tumble down the world rankings continues.