Poulter the man to beat in Tucson
Ian Poulter is the new favourite to win the WGC Match Play in Tucson, with Bubba Watson the only top-10 seed left in the tournament.
Tiger Woods is the only player to win back-to-back World Golf Championships since the series began in 1999, but Poulter now has the chance to join him in Arizona.
Five months after his heroics at the Ryder Cup and three months after he won the HSBC Champions in China, the 37-year-old takes on South African Tim Clark next for a place in the quarter-finals.
None of the top seven seeds are still alive after Friday's play saw Luke Donald, Louis Oosthuizen and Justin Rose follow Rory McIlroy, Woods, Adam Scott and Lee Westwood out of the event.
McIlroy's conqueror Shane Lowry - only playing because Phil Mickelson and Brandt Snedeker did not take up their places - is also through to the last 16 and he is now involved in another all-Irish clash against Graeme McDowell.
Poulter, winner of the title three years ago, has shown no ill-effects of taking six weeks off coming into the tournament.
"It feels pretty good," he said after following his win over Stephen Gallacher with a 3&1 success against American Bo Van Pelt.
"It was always a little risky taking that amount of time off, but it's working out pretty well.
"I worked hard at home, put some new irons in the bag and I couldn't be any fresher or fitter than I am right now.
"I didn't make any silly mistakes and I guess making seven birdies you are going to be tough to beat.
"The only mistake I made was I three-putted from 100 feet. Shucks!"
McDowell was in trouble against Alex Noren and trailed by one with one to play, but fired in an approach to four feet for a closing birdie and won when Noren strayed into the desert on the second extra hole.
Having beaten Padraig Harrington in the opening round, Lowry could be his second Irish scalp.
"It was a really tough, high quality match with Alex today so I am really pleased to have come through it," said McDowell.
"My match with Shane is going to be another tough one but a lot of fun and no matter what the result we will still be good mates afterwards. Hopefully!"
Donald's loss was the biggest shock of day three - and it was a real thumping.
The third seed, champion two years ago and never behind in any game that week, was crushed 7&6 by a player who went to the turn six under par having sunk a four-iron for an eagle two at the fifth.
"Scott played very well, I played just very average," Donald said. " I need to drive it well around this course. There's a few forced carries out there, and I probably didn't drive it well enough today to put any pressure on Scott. But he was 7 under through 12 and just playing extremely solid, didn't give me really a look.
"I had a few opportunities on the greens, but for whatever reason I was just not making the putts today, and hence I'm going home."
Rose lost 4&2 to Ryder Cup team-mate Nicolas Colsaerts, while three other Europeans still going are 2011 runner-up Martin Kaymer, Spaniard Gonzalo Fernandez-Castano and last man in Fredrik Jacobson.
Last 16 line-up: Lowry v McDowell, Day v B Watson; Garrigus v Jacobson, Kuchar v Colsaerts; Fernandez-Castano v Simpson, Mahan v Kaymer; Piercy v Stricker, Poulter v Clark.