Tiger Woods stayed on course for an eighth title in nine starts worldwide in Thursday's second round at the WGC-Accenture Match Play Championship as second seed Phil Mickelson was knocked out.
World number one Woods sealed a comfortable 3&2 win over fellow American Arron Oberholser but left-hander Mickelson was beaten 2&1 by 31st-seeded Stuart Appleby of Australia in a high-quality encounter.
Twice champion Woods, who fought back from three down with five holes remaining to edge big-hitting J.B. Holmes the previous day, rattled up five birdies in a flawless display.
The 32-year-old won the opening hole after Oberholser ended up in an unplayable lie in the desert scrub with his second shot and retained control for the rest of the match at Dove Mountain's Gallery Golf Club.
"I played a lot better today, hit the ball well and even made a couple of putts early on," Woods told reporters.
"I never gave Arron a hole. He had to earn the holes and I didn't make a bogey today. Match play is an animal that's all about the moment, you'd better get off to a quick start and never give holes away."
Woods, tournament champion at La Costa in 2003 and 2004, will face Aaron Baddeley in the third round, the Australian having gained a bye after the withdrawal of American David Toms due to a back injury.
Mickelson charged two up after eagling the par-five fifth but Appleby hit back with four birdies round the turn before sealing victory on the 17th green.
"It was really good, quality golf," Appleby said after covering the 17 holes in nine under par. "It was just a matter of me getting some shots together and sneaking my way ahead late in the day."
Mickelson, seven under for his round, added: "It was a good match but unfortunately I just didn't shoot low enough."
A resurgent Colin Montgomerie drew on Ryder Cup inspiration to edge American Charles Howell III one up in a fluctuating encounter.
The 44-year-old Briton, who eliminated world number seven Jim Furyk in the opening round, came from one down with five holes to play with three late birdies.
"I am delighted with the win," a smiling Montgomerie said. "After Charles had just birdied the 11th to go to all square, my caddie said to me: 'Right Mr. Montgomerie, it's Ryder Cup mode.' And I was four under from then on in."
Swede Henrik Stenson, the defending champion, beat South African Trevor Immelman after 25 holes, just one shy of equalling the two longest matches in the tournament's history.
American Scott Verplank outlasted Britain's Lee Westwood over 26 holes in the opening round in 2006, matching the record set by Canada's Mike Weir with his victory over American Loren Roberts in the first round in 2003.
American Boo Weekley came from two down after 10 holes to beat Spaniard Sergio Garcia 3&1 in another tight match.
Weekley birdied 16 and 17 to set up a third-round encounter with compatriot Woody Austin, who squeezed past Australian Adam Scott on the 19th hole.
In other matches, American Stewart Cink beat British Open champion Padraig Harrington of Ireland two up, Paul Casey edged fellow Briton Bradley Dredge 2&1 and Fiji's Vijay Singh scraped past Swede Niclas Fasth one up.
American Jonathan Byrd, conqueror of Ernie Els in the opening round, crushed Argentina's Andres Romero 6&4 and Rod Pampling hammered Nick O'Hern 5&4 in an all-Australian tie.