Tiger Woods blamed a ball mark for the shocking missed putt that ultimately led to his exit from the Accenture Match Play Championship last night.

Top seed Woods had a four-footer at the first extra hole to beat Australian Nick O'Hern, and everybody, including O'Hern, thought the match was as good as over.

But Woods sensationally missed his putt to the right, probably the shortest putt he has ever failed to hole when it really mattered.

"That's my fault for not paying attention to detail, something so simple," Woods lamented. "I was so enthralled with the line and I didn't see the ball mark.

"All I had to do was just fix it, and it's in. I knew if I hit it left-centre, the match is over. It hit the left side of the ball mark and knocked it right."

How much the ball mark really was to blame is probably something that only Woods and his caddie will ever know, because O'Hern was not even watching, just assuming the match was over.

But the gritty left-hander took full advantage of the reprieve and won with a par at the next, sneaking a 13-footer in the side door at Dove Mountain for his second win over Woods in three years in the World Golf Championships event.

"It's something to tell the grandkids," he said. "Not many people can say that. To beat him once was an amazing thrill and I'm sure he wanted to even the score today. I just knew if I played well I could do it again, because I've been in this situation before."

The short-hitting O'Hern did not exactly bring the course to its knees, but he did not have to, because Woods really struggled with his long game early, running up two double bogeys and conceding another hole without even getting to the green.

He was four-down after seven holes but it was inevitable he would come back, and so he did, making four birdies in the next five holes.

But O'Hern went to the last one-up after winning the par-five 17th, forcing Woods to make a birdie to extend the match. To nobody's surprise, Woods duly made birdie, knocking in a five-footer, and you could have got pretty good odds at that stage he would prevail in the play-off.

And so his seven-event winning streak in US PGA Tour events is over, although he lost four times times internationally while compiling the streak.

He officially tied for ninth here, the first time he has finished outside the top three in his past 12 starts worldwide.

"To go from July until now without ever finishing out of the top three, that's not bad," he said.

"I just didn't have control of my swing all day. I had a two-way miss going. The only thing that saved me coming in was the holes were downwind, so I couldn't hit it too far off line."

His exit left the tournament without any of the top eight seeds in the quarter-finals. The galleries may not know some of those left standing, but five of the top 16 seeds are still alive.

Three Europeans are through to the quarters - Englishmen Paul Casey and Justin Rose and Swede Henrik Stenson.

Casey will play defending champion Geoff Ogilvy of Australia, Rose meets South African Trevor Immelman, while Stenson faces giant killer O'Hern.

The other quarter pits American Chad Campbell and Canadian Stephen Ames, with Campbell the lone American still standing, which speaks volumes of just how international the sport has become.