By Mark Lamport-Stokes
MARANA, Arizona (Reuters) - While Tiger Woods was toiling in his match, fellow Americans Hunter Mahan and Dustin Johnson eased into the third round of the WGC-Accenture Match Play Championship with commanding victories on Thursday.
Mahan became the first player to advance, crushing South Korean Yang Yong-eun 5&3, and Johnson followed with a 7&5 demolition of Italy's Francesco Molinari at Dove Mountain's Ritz-Carlton Golf Club.
Three-times champion Woods, however, was one down to fellow American Nick Watney after 16 holes in his bid for a first PGA Tour victory in over two years.
British world number three Lee Westwood reached the third round for the first time in 12 appearances at the event, beating Swede Robert Karlsson 3&2, and fourth-ranked German Martin Kaymer edged past American David Toms two up.
In blazing desert sunshine, Mahan birdied six of the first eight holes to go four up on Yang and recovered from bogeys at the ninth and 10th to seal the win on the 15th green.
"I was playing as well as I could, hitting fairways and greens, giving myself good looks," Mahan told reporters after carding seven birdies and three bogeys.
"If you hit it good around here where these pins are and you get on the right level, you are going to have some putts, you are going to be able to make some putts. Today I was able to do that."
Johnson, who needed 20 holes to scrape past compatriot Jim Furyk in the opening round, never let up after seizing control against Molinari with four birdies in the first eight holes.
The match ended at the par-five 13th where the Italian parred and the big-hitting Johnson was just 10 feet from the hole in two shots.
"That momentum (from Wednesday) kind of carried over to today," Johnson said. "I got off to a good start and just played really solidly today."
American Steve Stricker, champion in 2001 when the event was held in Australia, won a tight encounter with South African Louis Oosthuizen one up after sinking a 20-foot birdie putt at the par-four 18th.
John Senden, who putted well on Dove Mountain's tricky greens, upset fellow Australian Jason Day, the world number seven, 6&5.
"I had the pressure on him early," said Senden, who birdied two of the first four holes to go two up. "Then from there I wanted to keep focused and keep the quality of shots going on.
"And then I did that. And he sort of made the mistakes to force the match to go further and further my way."
In other matches, Masters champion Charl Schwartzel of South Africa lost to South Korea's Bae Sang-moon one-down and second-ranked Northern Irishman Rory Mcllroy was three up on Dane Anders Hansen after 14 holes.
(Reporting by Mark Lamport-Stokes; Editing by Gene Cherry)