By Mark Lamport-Stokes
MARANA, Arizona (Reuters) - American Matt Kuchar became the first player to reach the quarter-finals of the WGC-Accenture Match Play Championship when he ousted German world number four Martin Kaymer 4&3 on Friday.
Kuchar came from one down after three holes with a rock-solid performance at Dove Mountain's Ritz-Carlton Golf Club as Kaymer, beaten by Luke Donald in last year's final, perpetually struggled on the tricky greens.
World number 14 Kuchar struck his tee shot to within two feet of the cup at the par-three sixth for a conceded birdie to go one up before his lead was doubled when Kaymer three-putted from six feet to bogey the par-five eighth.
The consistent American then birdied the 10th and 11th to go four up before sealing the win with a matching par on the 15th green.
Soon after, Hunter Mahan completed another upset when he stunned U.S. Ryder Cup team mate and world number five Steve Stricker 4&3 after a sizzling display in the Sonoran desert.
In-form Mahan piled up nine birdies in dazzling sunshine, the last of them conceded by Stricker from just two feet at the driveable par-four 15th to end the match.
British world number three Lee Westwood was three up on American Nick Watney after 14 holes while second-ranked Northern Irishman Rory McIlroy was three up on Spaniard Miguel Angel Jimenez after 10.
In other matches, Swede Peter Hanson was two up on American Brandt Snedeker after 12 holes and Mark Wilson was four up on fellow American Dustin Johnson, also after 12.
(Reporting by Mark Lamport-Stokes; Editing by Frank Pingue)