O'Hern (right) took the scalp of Tiger Woods in Tucson

Left-hander O'Hern was four up after seven but Woods fought back to level the match on the 15th before birdieing the 18th to force extra holes.

England's Justin Rose beat PGA Tour money leader Charles Howell III 3&2.

Also through to the last eight were holder Geoff Ogilvy, Paul Casey, Henrik Stenson and Trevor Immelman.

On a cold, blustery day at Dove Mountain, Woods' run of seven consecutive PGA Tour titles was brought to an end when O'Hern rattled in a 13-foot birdie putt on the second extra hole.

I knew he was going to come at me with birdies but the key is to stay patient and make pars Nick O'Hern

Woods, who also lost to O'Hern in the second round in 2005, had fought back with three straight birdies from the 10th but missed a five-foot putt for victory on the 19th.

The American, WGC Match Play champion in 2003 and 2004 at La Costa, had not finished worse than second on the PGA Tour since the Western Open last July.

Only fellow American Byron Nelson, with a run of 11 victories in 1945, has a superior winning streak on the US circuit.

"It's pretty special. We had a great match on the back nine especially," said O'Hern. "I was four up after seven which was pretty surprising.

"I knew he was going to come at me with birdies but the key is to stay patient and make pars."

In other matches, Australia's Ogilvy beat Sweden's Niclas Fasth 2&1 and Stenson brushed off Australian Aaron Baddeley 4&3.

Canada's Stephen Ames also progressed with a 3&1 win over American Stewart Cink, while Chad Campbell defeated fellow American David Toms by one hole.

In the quarter-finals, Casey will face close friend Ogilvy, O'Hern plays Stenson and Campbell takes on Ames.

I enjoyed my game against Mickelson - it was perceived as a big win but that meant nothing today Justin Rose

The Florida-based Rose, who beat world number three Phil Mickelson on Thursday, reached five up after nine against Howell III but had to wait until the 16th to seal victory.

"I'm pleased with that, especially the way Charles has been playing this year," said Rose, who will play South African Immelman, a 2&1 winner over England's Ian Poulter.

"The way I'm playing now, I feel very comfortable with my game, so I felt confident about not making too many unforced errors, which is difficult to beat in matchplay in those conditions.

"I certainly enjoyed my game against Phil (Mickelson). It was perceived as a big win but that meant nothing today.

"Yesterday was about the guy who was going to make the most birdies, whereas today it was a lot more about who was going to keep their ball under control."

Casey was never behind against Micheel in a re-match of last September's Wentworth World Match Play final but he let slip a three-hole lead after 10 before winning two up.

"This is going pretty well. I'm really enjoying this experience," said Casey, who has also beaten Mike Weir, Colin Montgomerie and Micheel in a mirror image of his Wentworth triumph.

"It's very strange how it's panned out but maybe that's a good omen."