Ireland’s Shane Lowry recorded a famous victory over World Number One Rory McIlroy at the WGC-Accenture Match Play Championship.
A team-mate of McIlroy back in their amateur days, Lowry marked his debut in the event with a last-green victory he will long remember for the way he followed chip-ins at the 11th and 12th with a conceded eagle on the next to go two up.
Golf's hottest young property won the 14th and 16th, but in between hacked left-handed into a bunker from the edge of a cactus bush and then sent his third shot flying over the green into more trouble.
There was just enough light for them to finish and although Lowry found two bunkers on the last McIlroy followed him into the greenside sand and after he had almost holed Lowry got up and down to win.
It is the third time in four years at the event that the top seed has gone out straightaway. Luke Donald lost last year to Ernie Els and in 2010 Steve Stricker was beaten by Ross McGowan.
McIlroy said: "I drove really well, but couldn't take advantage of that. If I'd hit my irons better it could have been a different story.
"I could have been three or four up early, but let him get back in the match and he had a nice little run.
"I just left myself a little bit too much to do."
As he spoke second seed Tiger Woods was beaten as well, going down 2 and 1 to fellow American Charles Howell III.
A three-time winner of the title, it was also the third time Woods has gone out in the first round. Peter O'Malley and Thomas Björn have previously beaten him at the same stage.
Lowry stated: "To make par on the last was great and to beat him was even better.
"My knees were knocking over that final putt. I managed a couple of chip-ins which were huge - I had a bit of luck that I needed and I said to my caddie that he's not going to be liking this at all."
There was a danger of the top three seeds all going out when 2011 winner Donald came to the last all square with German Marcel Siem, but he birdied it from ten feet.
In the other all-Irish clash Graeme McDowell beat Padraig Harrington one-up, while Spain’s Rafael Cabrera-Bello came from behind to win against Lee Westwood.
There were wins too for 2010 winner Ian Poulter and Justin Rose, the former taking out last month’s Omega Dubai Desert Classic winner Stephen Gallacher 2 and 1.
Fourth seed Louis Oosthuizen also progressed against Scottish opposition; Richie Ramsay failing to hold onto a two hole lead after 11 against the South African, who won on the 17th.
Thorbjørn Olesen won the battle of the debutants against Jamie Donaldson, the only Welsh representative, with a 3 and 2 victory over the player who pushed him into second place in Abu Dhabi last month.
It will be Rose against Ryder Cup team-mate Nicolas Colsaerts next following contrasting victories.
The Belgian easily dispatched American Bill Haas 5 and 4, but Rose breathed a huge sigh of relief when he saw off South Korean K J Choi following the loss of a four hole lead.
Fifth seed Rose was even in danger of falling behind at the 15th, but sank a 15 foot birdie putt and Choi missed from 12.
He did not even need to putt two holes later as his 42 year old opponent got in trouble and conceded, but Rose said: "I said at the beginning of the week it comes down to that one moment in the round where you need to make something happen.
"That moment for me was on 15. I was looking like I was going one down. To make a putt when I really needed it feels good and I felt like that's what I've begun to do a lot recently.
"It'll be a tough game against Nicolas, but obviously one that I'm looking forward to - and I'll have to make some birdies."
One of the day’s best performances came from Swede Alex Noren, who thrashed US Ryder Cup star Dustin Johnson 6 and 4 to set up a meeting with McDowell.
“I played great,” said Noren. “I was really happy with my game and hit a lot of greens, which made it feel easier than it can on this course.”
Noren’s compatriot Peter Hanson ensured at least eight of Europe’s victorious Ryder Cup side will be in the last 32 after winning his Scandinavian duel with Björn 3 and 2.
Cabrera-Bello will now face Martin Kaymer, the German overcoming South African George Coetzee, while Spain’s Gonzalo Fernandez-Castaño and Italian Francesco Molinari will have to return in the morning with their match all square with three to play after darkness prevented them finishing.
Australian Marcus Fraser was another player to cause an upset – he knocked out former US PGA Championship winner Keegan Bradley - and now faces Swede Fredrik Jacobson, who eliminated Els at the 18th.
“Keegan is a Major winner and Ryder Cup player, so he's used to match play,” said Fraser.
“Down the stretch he's probably one of the best in the game. It wasn't the prettiest match; we were probably both around level par, but as I said before, it's match play, you can play really well and get rolled or you can play average and hang in there.
“That's what I did today, hung in there and made a nice putt on 17, which really helped. That was a good sort of 30 footer down the hill.
“I just backed myself - that was the difference. Normally standing there pretty negative, but I stood there on the back nine and backed myself, and it was nice to come away with a win.”