England's Ross McGowan, only playing because Tiger Woods and Phil Mickelson chose not to, knocked top seed Steve Stricker out of the World Golf Championships-Accenture Match Play Championship in Tucson on a good day for The European Tour contingent.
With a 25 foot par putt on the first extra hole McGowan grabbed the biggest possible scalp on a day which also saw Rory McIlroy come from four down to win, but Padraig Harrington and Ross Fisher among those beaten.
Stricker went to World Number Two when he won the Northern Trust Open in Los Angeles two weeks ago, but his defeat opens the door for Lee Westwood to move into that spot this weekend.
The Race to Dubai champion would have to win the title for that, but he made a good start by overcoming fellow Englishman Chris Wood 3 and 1.
"It was a bit scrappy, but after the first five holes I felt like I took control of it," said Westwood.
"Chris came back and made a couple of birdies on ten and 11, and I missed one on 11 from about four feet to halve.
"Really it was just cat and mouse, just good enough to win the match, which sometimes what you have to do in match play."
McGowan, who leapt up the world rankings when he finished runner-up to Westwood at the Dubai World Championship presented by: DP World in November, was still a massive underdog against Stricker.
He becomes only the second 64th seed to beat the top seed in the history of the event. Australian Peter O'Malley eliminated Tiger Woods in 2002.
“It feels pretty good,” said McGowan. “I would say I fancied my chances, I knew I had a good chance at the beginning of the day.
“I had a shaking start, but played really nicely from about the fifth or sixth. It is nice to win and get through for tomorrow.”
McIlroy, meanwhile, pulled off a brilliant victory from the jaws of defeat.
He lost four of the first six holes to American Kevin Na early on and was still two behind with only four left.
But the 20 year old fourth seed eagled the next and won on the final green as Na, ranked 61st in the world, crumbled.
It was just the sort of thing that would have hugely impressed Ryder Cup Captain Colin Montgomerie, who earlier this week said: "I want to see guys who show guts and determination, guys who are maybe two or three down with four or five holes to play but who battle back to win."
The young Northern Irishman, a strong candidate for a debut against the Americans in October, reached the quarter-finals last year.
There was a superb fightback from Ian Poulter as well. He went from two up to two down against former Open Championship winner Justin Leonard, but won on the 19th and now faces Australia’s Adam Scott.
Out, though, went three-time Major winner Harrington to Indian Jeev Milkha Singh by a 3 and 1 margin and Fisher, winner of the Volvo World Match Play Championship in Spain last October, by 5 and 4 to Thai Thongchai Jaidee.
McIlroy is already the only Irishman left in the event as it moves down to the last 32, Graeme McDowell having gone down 2 and 1 to in-form Luke Donald.
Paul Casey, last year's runner-up to Australian Geoff Ogilvy, had a resounding 5 and 4 success over Canadian Stephen Ames, but that was far from the biggest victory of the day.
Ames' compatriot Mike Weir defeated big-hitting Spaniard Alvaro Quiros 8 and 6 - he birdied nine of the first ten holes - and will now take on Casey, while Ogilvy began his defence with a 7 and 5 win over Alex Noren.
It was not a good day for the Swedes. As well as Noren, Peter Hanson lost to Australian Robert Allenby and former winner Henrik Stenson withdrew after one hole against American Ben Crane because of flu-like symptoms.
McIlroy said: "I definitely didn't make it easy for myself. I got off to a very slow start.
"I think I hung in well, but was pretty fortunate to get through and I'll need to play better if I want to progress into the latter stages."
He next faces Oliver Wilson, who had a fine win over Omega Dubai Desert Classic winner Miguel Angel Jiménez, and added: "Ollie's a great competitor, a Ryder Cup player and he's going to be very tough."
McDowell commented: "The last two years I've run into a buzz-saw.
"Last year Zach Johnson made eight or nine birdies and Luke just putted the eyes out of it. Every time I smelt a chance he made a putt.
"It does not matter how well you play in this. If someone plays better you go home."
England's Simon Dyson also made an early exit, going down to American Sean O'Hair, but Europe have Swede Robert Karlsson, Dane Anders Hansen, German Martin Kaymer and Spain's Sergio Garcia in the last 32 as well as McGowan, McIlroy, Westwood, Poulter, Donald, Casey and Wilson.
Kaymer birdied the last four holes to beat Chad Campbell, while Hansen beat US Open Championship winner Stewart Cink, but Italian brothers Edoardo and Francesco Molinari both lost - Edoardo from four up with nine to play against Open Championship winner Stewart Cink.
One of the stand-out second round ties sees South African European Tour Members Ernie Els and Retief Goosen go head-to-head.
“Obviously I'm up against one of the big match play players tomorrow,” said Goosen. “But you've got to go out there and try to make a birdie on every hole and see what happens.”
Elsewhere there were wins for January’s European Tour Golfer of the Month Charl Schwartzel, Colombian Camilo Villegas and US PGA Championship winner Y E Yang.