Masters champion Jordan Spieth was sent crashing out of the $9.25 million WGC-Championship Match Play on Friday after England's Lee Westwood held his nerve to win a thrilling duel and clinch a place in the last 16.

European Ryder Cup star Westwood recovered from losing the opening two holes to battle back and go one up after draining a 10-foot birdie putt on the 17th at an overcast Harding Park in San Francisco.

Spieth was unable to wrest back the initiative on the 18th, and conceded to give Westwood a two-up victory which sees the 42-year-old English veteran advance to Saturday's knockout rounds.

"Today I had nothing to lose," a delighted Westwood said. "Jordan is arguably the best player in the world at the moment so it was nice to be the underdog for a change.

"I'm pleased with the way I got through it coming down the stretch."

Spieth was philosophical in defeat, saying he was satisfied with his form despite the loss.

"I just had a tough opponent," the 21-year-old prodigy said.

"I've no complaints -- I was 16 under in three rounds. But it's Match Play, so what are you going to do?

"I'm excited about the way I'm playing, it's just a shame it ended like that today."

Both Westwood and Spieth had won their opening round-robin games to set up a winner-takes-all scenario in their final Group 2 game.

The match hinged on a dramatic recovery from Westwood on the 16th when he appeared to have gifted Spieth the lead.

After landing a tee-shot in the bunker, Westwood mis-hit his recovery through the back of the green. A disastrous third shot then landed in the rough just off the green, leaving Spieth poised to go one up.

But Westwood conjured a superb chip-in to halve the hole and then took the lead on the par-three 17th when Spieth's tee shot landed well wide of the pin.

The format for this year's tournament was overhauled to eliminate the possibility of early round exits for top players.

The field has been split into 16 groups of four players, with the group winners advancing to the knockout rounds over the weekend.
Source: AFP