Mickelson, Dustin Johnson roll into last 16

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Phil Mickelson dominated J.B. Holmes to remain undefeated and reach the weekend at the WGC Dell Technologies Match Play for the first time since 2004.

Mickelson has been so good over the first three days at Austin Country Club that he is yet to trail, having thrashed Holmes 6 and 5 on Friday.

The world number 18 joked that he was able to "conserve energy" by not having a match pushed past the 15th hole.

"I'm nervous that I haven't been in a match that has gone the last hole or two and feel that clutch pressure," he said, via GolfChannel.com. "But also the good is that I have been able to conserve energy heading into this weekend."

This is rare territory for Mickelson, 46, who has played in 13 Match Play events, but only once on the weekend, when he lost to Davis Love III in the quarter-finals of the 2004 event.

Mickelson will play Marc Leishman in the last 16.

Another player who dominated group play was Dustin Johnson, who completed his own sweep Friday with a 5 and 3 win over Jimmy Walker.

It will be a Johnson and Johnson matchup on Saturday with Dustin playing Zach, who survived to win Group 16.

Jordan Spieth could only halve his match against Ryan Moore, but even a win would not have been enough to take him past Hideto Tanihara in Group Five.

Facing a player he long has looked up to, Jon Rahm, 22, defeated fellow Spaniard Sergio Garcia 6 and 4 to advance to Saturday's play.

Rahm will take on Charles Howell III, who won a sudden-death play-off against Rafa Cabrera Bello and Tyrrell Hatton on the fifth hole with a birdie from four feet to advance as the Group 10 winner.

Hatton was disqualified when he incurred a two-stroke penalty, holing out after the ball had moved when he placed his putter behind it.

Kevin Na needed only one hole in his play-off against Matthew Fitzpatrick to win Group Six.

Na's next opponent will be Bill Haas, who needed six play-off holes to outlast K.T. Kim in Group 11.

William McGirt and Paul Casey also finished pool play unbeaten at 3-0.

Bubba Watson and Ross Fisher will square off Saturday after they won their respective groups.