“I don’t know if my heart is beating at the normal rate, but I don’t think so,” said the 31-year-old, who went into a slump after playing in Europe’s Ryder Cup triumph at Valderrama in 1997.

“I didn’t expect this. I’m making big swing changes and the last few months I’ve not been playing great.

“I expected some results this year, but apart from the majors to me this is the best tournament to win. It means an awful lot.”

In a week dominated by Annika Sorenstam playing on the US Tour, victory on this side of the Atlantic perhaps fittingly went to the only man to have appeared on the women’s circuit. Garrido’s girlfriend is professional Samantha Head and he has caddied for her a few times.

He and Immelman finished tied on the 18 under par total of 270, Immelman almost making an 80-foot eagle putt on the last.

Back they went to the 18th tee and when Garrido pushed his second and the Cape Town golfer, who had also birdied the 17th in regulation play, was on the green in two again it was definitely advantage Immelman.

But Garrido, whose father Antonio played in the Ryder Cup as well, came down in the clear rather than the trees and from 50 yards he pitched brilliantly to two feet.

Immelman, from 60 feet this time, left his eagle attempt five feet short and when he missed that he feared it was over. It was.

“Man I thought I had holed at the 72nd – even though I’m so small I couldn’t really see the hole,” said Immelman, whose consolation was a cheque for £276,365.

“But what can you say? He shot 65 and made a great up and down in the play-off.”

Sweden’s Mathias Gronberg, winner of the Italian Open three weeks ago, finished third three strokes behind and world number two Ernie Els – three times a runner-up at the event, but never a winner – was fourth.

“They just weren’t going in,” said Els, who watched Immelman shoot 64 in the third round and then partnered Garrido on the final afternoon.

“Definitely I’ve got to work on my short game – it let me down.”

Garrido praised the part Els played in his win.

“People might think that playing with Ernie is a difficult thing, but he’s such a nice guy and such a help. He supported me and made it easy.”

Nick Faldo finished joint ninth with Paul Casey and Colin Montgomerie and all three were disappointed with that.

Faldo, appearing in the event for the 25th time, was chasing a record fifth title and at five behind with a round felt he had an outside chance. But a 70 was never going to be enough.

“I played well, but couldn’t get it in the hole,” said the 45-year-old, third and fourth the past two years.

“I thought I could go out and have a really good day, but I made only one or two putts and that’s not good enough.

“It’s good to be in contention again, though, and my game is very solid. Hopefully the US Open next month is set up as tough as Hell so that half of them are screaming.”

Last June Faldo finished fifth there.

Faldo believes the West Course needs modernising. In fact, he has believed it for a decade or more.

He said: “Some of the bunkers are obsolete. I’ve been saying it for ages and had meetings back in 1993 I think, but nothing’s happened yet.”

Casey was hoping for back-to-back wins on British soil after his Benson & Hedges International Open at The Belfry.

But a triple bogey seven on the third put him eight adrift, and five back nine birdies came too late.

Montgomerie’s goal was a fourth win in five years, but he gave himself no chance from six back at the start of the day and was right. He shot a 69.