In the space of 30 minutes the 36-year-old went from having a near-albatross to tangling with a bush with one hand in his pocket and salvaging par with a 40-foot putt.

It was the sort of rescue act that Montgomerie and defending champion Padraig Harrington were unable to produce.

The former, whose 88th position on the world rankings represents his lowest standing in the game since 1990, managed only a 75 after running up a double-bogey seven on the 528-yard seventh.

Harrington, meanwhile, returned a 72 that included a bogey six on the long 18th after he hooked his drive into the River Maigue.

Darren Clarke also shot 72, Paul McGinley 73 and Lee Westwood 75, but their 19-year-old stablemate Rory McIlroy is well in touch following his 70.

Former Volvo Masters champion Singh hit a three-wood to a foot on the seventh for his eagle, but found the bushes behind the green with his pitch to the 631-yard ninth.

“The first thing was to get a ref to make sure I didn’t break any rules,” he explained.

“You can’t touch anything and that’s why I put my hand in my pocket and took it out when I had to grip the club.

“My backswing was about a foot and a half and I was more worried about just hitting the ball. It could have gone anywhere.”

He was happy enough with getting it on the green and making the 40-footer was just icing on the cake.

Singh, son of an Olympic running star, has already finished second twice on the European Tour this season, losing a play-off to Graeme McDowell in Korea a week after a freak accident when his caddie drove a golf cart into a palm tree.

“I never thought that carts could be that dangerous. I went flying, banging my head against the windscreen and bouncing out.”

With regard to Montgomerie’s pre-Masters comments that inviting Asians for commercial rather than golfing reasons was “a strange way to make up a field for a major championship”, Singh bears no grudge.

“I just thought it was his opinion. I can only say I was thankful.”

He finished 25th – and is now five places ahead of the Scot on the world rankings.

Green is playing his first event since missing the cut at Augusta, but has been practising hard at home in Melbourne and it showed with four birdies in his first seven holes and then three more in the last five.

Fourth in last year’s Open at Carnoustie after a brilliant closing 64, the 37-year-old commented: “I concentrated on concentrating hard and it worked out pretty well.”

Harrington strapped his arm because of some trouble with tennis elbow and said: “I’ve just been struggling to get on top of it, but it’s not affecting my golf whatsoever.

“I made a few mental errors and seemed to drift away a bit. I suppose 72 doesn’t look that good when you see six under, but that won’t have played me out (of contention) at this stage.

“But it was probably the easiest day you’ll ever get on this course in terms of weather and so there was an opportunity out there.

“I just have to play my best golf over the next three days.”