Ernie Els rolled back the years to bring Luke Donald's defence of the World Golf Championships-Accenture Match Play title to an abrupt halt.
England's World Number One became only the third top seed to lose in the first round as Els produced the sort of form that landed him three Major Championships in a 5 and 4 victory.
It was all the more remarkable as Els was not even in the field for the Tucson event until Phil Mickelson pulled out.
In winning last year Donald was never behind in six games and never taken to the final green either.
But on his return to Dove Mountain the 34 year old, who like Els finished the Northern Trust Open in Los Angeles on Sunday with a seven over par 78, trailed from the third hole.
Els, a giant of the game now in the role of giant-killer, finished things off with a ten foot birdie putt on the 14th.
"Luke had such an unbelievable year last year, winning both money list titles," he said. "I knew I had to play well and I did."
Donald joins Tiger Woods and Steve Stricker in making an instant exit as top seed. They lost to Peter O'Malley and Ross McGowan respectively in 2002 and 2010.
Three-time champion Woods came from behind for a one hole victory over Spain's Gonzalo Fernandez-Castaño.
In a generally scrappy match the Madrid golfer won the first two holes. Woods hit back to lead by one after eight, then hit wild shots and lost the tenth and 11th, but took the 15th and 16th and just held on.
Bunkered in two on the last with Fernandez-Castaño only nine feet away, he splashed out superbly down the slope to eight feet and was the one to make his putt.
Robert Rock, conqueror of Woods and the Official World Golf Ranking's top four in Abu Dhabi last month, grabbed another notable scalp when he beat World Number Eight Adam Scott.
That came on the last, as did the victories by Scots Paul Lawrie and Martin Laird over Justin Rose and Alvaro Quiros respectively in two of six all-European clashes.
Lawrie, winner of the Commercialbank Qatar Masters three weeks ago, is making his first appearance in the tournament since 2003 and said: "It's great, but there is no point in playing these events if you are not going to play very well."
Second seed Rory McIlroy, left as Ireland's only hope after Graeme McDowell and Open Champion Darren Clarke lost, trailed South African George Coetzee at the turn, but won the 11th and 12th to turn things round and eventually clung on for victory at the final green.
McDowell lost to Korean Y E Yang for the second year running and said: "I made six birdies and played decent golf, but I ran into a man who played extremely well.
"He didn't put a foot wrong, but that's just the way the cookie crumbles with this tournament.
"He seems to have my number a little bit - and I have a tendency to bring out the best in guys around this track for some reason."
Clarke was beaten 5 and 4 by American Nick Watney, who next faces Woods, but Lee Westwood - never beyond the second round in 11 previous trips - overcame Belgian Nicolas Colsaerts.
He and Rock are the only English survivors, Simon Dyson bowing out like Donald, Ian Poulter and Rose.
Poulter, winner two years ago, suffered a 4 and 3 defeat to Korean Bae Sang-moon.
Donald said: "I’m not sure where to start - I just didn't play well. It's disappointing. I've worked hard and to lose control of the ball is frustrating.
"I felt pretty good about where I was and I'm not sure what happened. Hopefully it’s just one of those bad days."
Westwood, who won on the 17th, said: "I didn't make a bogey and it was a good match. You can't cruise your way into the tournament, as I do in a lot of them."
He has European opposition again in the second round, Robert Karlsson beating fellow Swede Fredrik Jacobson.
Donald's defeat means Westwood and McIlroy, relieved to win on the last after bogeying the 16th and 17th, could become World Number One this week, but they each need to win the title.
Germany’s Martin Kaymer safely progressed with a 4 and 2 victory over Greg Chalmers, and now faces veteran American David Toms.
Former Open Champion Louis Oosthuizen beat Australian Aaron Baddeley, while Italy’s Matteo Manassero produced one of the performances of the day to see off World Number Six Webb Simpson 3 and 2.
Miguel Angel Jiménez was another to overturn the formbook, seeing off compatriot Sergio Garcia, while Dane Anders Hansen, Masters Tournament winner Charl Schwartzel and Italy’s Francesco Molinari were the other European Tour Members to secure a place in the last 32.
