Henrik Stenson overcame the curse of the top seed with a late fightback against Kiradech Aphibarnrat on day one of the WGC-Accenture Match Play.
The European Number One won three holes out of four from the 14th, where his Thai opponent three putted, to progress to round two at the Golf Club at Dove Mountain – only the second time in the last five years that the number one seeded player has gone past the first round.
The win also represented a first in Arizona in five attempts for the Swede, who won this event at the Gallery Golf Club in 2007.
“I'm still in shock,” said Stenson. “It was a tough match, Kiradech is a good player.
“I struggle a bit on this course to be honest - it doesn't really fit my eye. A lot of times if you fly a bunker, you're bouncing through the fairway and you have to thread it in.”
Stenson will face South African Louis Oosthuizen in the last 32, after the former Open Champion held on to beat Nick Watney one up.
Thomas Björn avenged his 2012 first round defeat to Francesco Molinari - the Dane was knocked out by the Italian at the 20th hole two years ago, but this time progressed 2 and 1 to reach round two for only the second time in ten years.
“It's not very nice to come into this tournament and play your good friends in the first round, but that happens,” said Race to Dubai leader Björn, who next faces American Jordan Spieth.
“I played nice today. I was bit rusty as I’ve been sick for a couple weeks. Coming in, I didn't have really good preparation, so it was a bit rusty early on.
“There was a little bit of trying to get over the line in the end, but I got it done. I played some really good stuff in the middle there.
“Francesco never goes away - that's one thing you have got to give him. He stuck in there; every time I got to two up, he would have a great shot on the hole after and got himself back to one, so it was a tight match and it could have swung either way. He probably didn't putt as well as he would have liked to.”
Former champion Ian Poulter suffered his third first round exit in four years, but Graeme McDowell joined Ryder Cup team-mates Rory McIlroy, Sergio Garcia, Justin Rose and Peter Hanson in the last 32 thanks to an unlikely comeback against Gary Woodland.
McDowell was four down after seven holes and still three down with three to play, but won the 16th with a par, the 17th with a birdie and was conceded the 18th when Woodland went from one greenside bunker to another.
A birdie on the first extra hole then sealed victory over a shell-shocked Woodland, with whom he had shared a private jet from Florida to Arizona.
"I missed a short one on 15 to follow him in for birdie and he looked unbeatable," McDowell admitted. "He hit a six iron all over the flag on the 16th and I thought my manager had a plane ticket booked for me and I was going home.
"I feel very fortunate to have got through that match. Just when you think you are dead and buried, you get a little luck from the gods. Gary is a good friend and a great player and I think he's one to watch this year."
Poulter earlier lost 2 and 1 to American Rickie Fowler, who led from the fourth hole onwards and will now face compatriot Jimmy Walker in the second round. Walker, who has already won three times this season, secured the first victory of the day with a comfortable 5 and 4 win over South African Branden Grace.
McIlroy lost to Shane Lowry in the first round 12 months ago but had a comfortable 3 and 2 win over Boo Weekley that set up a last-32 clash with Harris English, who beat former World Number One Lee Westwood 5 and 3. Another former Number One, compatriot Luke Donald, also made an early exit as he was downed 5 and 4 by Matteo Manassero.
"I played well I guess for the first 12 holes," said McIlroy, whose wayward second shot on the 15th had spectators ducking for cover and saw one unfortunate man covered in cactus stems known as 'Jumping Cholla'.
"I might have got a bit complacent the last few holes and gave Boo a couple but I'm just happy to get through to the next round."
Five matches went to extra holes, Garcia beating Marc Leishman on the 22nd, Brandt Snedeker seeing off David Lynn on the 20th and Jason Dufner edging past Scott Stallings on the 19th.
And in the last match of the day, Ernie Els beat Stephen Gallacher after the Scot squandered a two-hole lead with three to play, the Dubai Desert Classic winner losing the 16th and 17th to par, missing from five feet for a winning birdie on the 18th and then making a bogey on the 19th.
Finland's Mikko Ilonen had looked like creating a shock when he led the in-form Bubba Watson by two holes with six to play, but lost the next three holes and Watson - who claimed his first win since the 2012 Masters in the Northern Trust Open on Sunday - sealed a 2 and 1 win on the 17th.
Defending champion Matt Kuchar also advanced to the second round, but only after having to 'win' his match with Austria's Bernd Wiesberger twice.
Kuchar thought he had sealed a 5 and 4 win on the 14th, only to realise he had failed to move his ball marker back to its correct position before holing a birdie putt. That cost him the hole and meant the match continued, but the World Number Ten still had a three-hole cushion and eventually won 3 and 2.
Hanson beat Dustin Johnson 4 and 3 to set up a meeting with France's Victor Dubuisson, who saw off Kevin Streelman 5 and 4.
Sweden's Jonas Blixt enjoyed a 2 and 1 win over former US PGA Champion Keegan Bradley and South African George Coetzee saw off Steve Stricker 3 and 1. Stricker's participation in the event had been in doubt until his brother underwent a successful liver transplant at the weekend.
The biggest margin of victory belonged to American Billy Horschel, who beat Welshman Jamie Donaldson 6 and 5, while Bill Haas beat Miguel Angel Jimenez 5 and 4 and US Open Champion Justin Rose was taken to the 18th before edging past Scott Piercy.
In total 15 European Tour Members made it through to round two, with South African pair Charl Schwartzel and Richard Sterne through to face Jim Furyk and Hunter Mahan respectively.
