English golfer Lee Westwood's reached the last eight for the first time at the WGC Match Play Championships at Dove Mountain's Ritz-Carlton Golf Club.
Germany's Martin Kaymer became the biggest casualty in the third round.
World number three Westwood never trailed on his way to a 3&2 victory over American Nick Watney but Kaymer, beaten by Luke Donald in last year's final, was ousted 4&3 by American Matt Kuchar.
Hunter Mahan completed another upset when he stunned US Ryder Cup team mate and world number five Steve Stricker 4&3 after a sizzling display in the Sonoran desert and Northern Irish world number two Rory McIlroy beat Spaniard Miguel Angel Jimenez 3&1.
In other matches, Swede Peter Hanson advanced with a 5&3 win over American Brandt Snedeker while South Korea's Bae Sang-moon won a tight tussle with Australian John Senden one up.
Tiger Woods was ousted by Watney the day before.