LOS ANGELES (AFP) - World No. 1 Dustin Johnson and five-time Major winner Phil Mickelson advanced to the knockout rounds of the World Golf Championships Matchplay Championship with impressive triumphs on Friday.
Johnson, the US Open champion, won six of the first seven holes and completed an unbeaten run through the group stage by downing fellow American Jimmy Walker 5& 3 at Austin Country Club.
Johnson had two birdies and an eagle on his way to leading 6-up after seven holes and even a birdie-eagle run by Walker to win the 11th and 12th only delayed the end, which came when Johnson parred the 15th to close out the win.
In Saturday's round of 16, Johnson faces compatriot Zach Johnson, who edged out American Brendan Steele 1-up in the day's final match to advance.
Steele, who only needed to halve to go through, birdied the par-five 16th and par-three 17th to square his match but Johnson pitched his third shot three feet from the cup and parred the 18th while Steele missed a 12-footer for par to fall.
Mickelson finished group play unbeaten after a 6&5 rout of fellow American J.B. Holmes. It's the first time since 2004 that the 46-year-old US left-hander has advanced past the third round of the event.
Mickelson dominated from the outset, opening with back-to-back birdies before going 3-up after three holes. He won the eighth with a birdie before taking the 10th and 11th and then closing out the win with a half at the 13th.
England's Paul Casey downed South Africa's Charl Schwartzel 4&3 in the only match-up of 2-0 players while Jon Rahm downed fellow Spaniard Sergio Garcia 6&4.
Schwartzel birdied the first hole to seize the lead over Casey, but the Englishman squared the match with a par at the fourth and never trailed again.
In the round of 16, Mickelson will face Australia's Marc Leishman while Casey meets Japan's Hideto Tanihara and Rahm plays American Charles Howell, who survived a three-man playoff to advance.
Several sudden-death playoffs were needed to decide who advanced after deadlocks in group play.
American Kevin Na birdied the first playoff hole to down England's Matthew Fitzpatrick and book a last-16 date with compatriot Bill Haas, who birdied the sixth playoff hole to defeat South Korea's K.T. Kim.
Leishman, last week's Arnold Palmer Invitational winner, birdied the second playoff hole to advance over England's Lee Westwood and American Pat Perez.
Howell birdied the fifth playoff hole to beat Spain's Rafael Cabrera Bello. England's Tyrell Hatton had dropped out after the first extra hole with a double bogey after calling a two-stroke penalty on himself.
World No. 2 Rory McIlroy, already eliminated by Dane Soren Kjeldsen, rallied to halve with Argentina's Emiliano Grillo.
"It's odd whenever you have nothing to play for," McIlroy said. "I guess that's both of our faults. We didn't win our matches on the first day."
Kjeldsen will next face American William McGirt while other knockout openers match Sweden's Alex Noren and American Brooks Koepka plus two-time Masters champion Bubba Watson and England's Ross Fisher.