Marana - Luke Donald and Louis Oosthuizen followed Rory McIlroy and Tiger Woods out of the World Golf Championships Match Play Championship on Friday with second-round defeats.
One day after the fickle nature of the match play format was amply demonstrated by the first-round upsets of world number one McIlroy and number two Woods, seeds continued to tumble.
VIDEO: WGC-Match Play, Day 3 highlights
American Scott Piercy thumped England's world No 3 Donald 7 and 6, taking the lead at the first hole where Donald opened with a double bogey.
Piercy won the next two holes with a birdie followed by another bogey from Donald, and went 4-up at the fifth when he holed out from more than 200 yards away for an eagle.
He sealed the match with one last birdie, sinking a four-footer to close it out at 12. His victory over the 2011 winner of this World Golf Championships event was the most lopsided result of the week so far.
"I played well, and he was off a little bit," Piercy said. "That's why it looked so one-sided."
Donald, who characterised his game as "just very average," was the top seed in his quarter and third seed overall in the 64-man field behind world No 1 McIlroy and No 2 Woods, who both fell in the snow-delayed first round on Thursday.
Fourth overall seed Oosthuizen, a former Masters champion from South Africa, joined the exodus of bracket leaders as he was beaten 3 and 2 by American Robert Garrigus.
England's Justin Rose, the overall fifth seed, was also on his way home, falling 4 and 2 to Belgian Nicolas Colsaerts.
It marked the third time in the last five years that the top four seeds failed to make it past the second round.
By the end of the day, reigning Masters champion Bubba Watson was the only one of the tournament's top 10 seeds remaining - and only after battling to a victory over Jim Furyk at the 22nd hole.
"This game... it's a toss-up," Watson said. "You can't really judge who's going to win, or bet who's going to win. It really means nothing."
Ireland's Shane Lowry showed no letdown after his triumph over McIlroy, advancing with a convincing 6 and 5 victory over Sweden's Carl Pettersson.
He's the first 64th seed to reach the third round in the 15-year history of the event.
Lowry booked a third-round match against another old friend from Northern Ireland, Graeme McDowell -- who finally put away Sweden's Alexander Noren at the 20th hole.
"I struggled to get to sleep last night," Lowry admitted. "I played solid all day. I made a few birdies and didn't do anything wrong, which is key in match play."
Friday's second round was a day behind schedule after a desert snowstorm cut short play on Wednesday.
Organizers planned to get back on track with third-round matches on Saturday morning followed by quarter-finals in the afternoon.
US Open champion Webb Simpson moved on with a 1-up win over Sweden's Peter Hanson.
Simpson next faces Spain's Gonzalo Fernandez-Castano, who cruised to a 6 and 5 victory over American Charles Howell a day after Howell outdueled Woods.
Defending champion Hunter Mahan defeated South African Richard Sterne 4 and 3 and former champion Ian Poulter of England downed American Bo Van Pelt 3 and 1.Collated second-round scores on Friday in the World Golf Championships Match Play Championship:
Shane Lowry (IRL) bt Carl Pettersson (SWE) 6 and 5
Graeme McDowell (NIR) bt Alexander Noren (SWE) 20 holes
Bubba Watson (USA) bt Jim Furyk (USA) 22 holes
Jason Day (AUS) bt Russell Henley (USA) 19 holes
Robert Garrigus (USA) bt Louis Oosthuizen (RSA) 3 and 2
Fredrik Jacobson (SWE) bt Marcus Fraser (AUS) 4 and 3
Nicolas Colsaerts (BEL) bt Justin Rose (ENG) 4 and 2
Matt Kuchar (USA) bt Sergio Garcia (ESP) 2 and 1
Gonzalo Fernandez-Castano (ESP) bt Charles Howell (USA) 6 and 5
Webb Simpson (USA) bt Peter Hanson (SWE) 1-up
Martin Kaymer (GER) bt Rafael Cabrera-Bello (ESP) 2 and 1
Hunter Mahan (USA) bt Richard Sterne (RSA) 4 and 3
Scott Piercy (USA) bt Luke Donald (ENG) 7 and 6
Steve Stricker (USA) bt Nick Watney (USA) 21 holes
Tim Clark (RSA) bt Thorbjorn Olesen (DEN) 3 and 2
Ian Poulter (ENG) bt Bo Van Pelt (USA) 3 and 1