In the end the 28-year-old’s one-under-par 72 proved just good enough for a one-stroke victory over fellow Englishman Andrew Marshall and Denmark’s Soren Hansen.

Montgomerie, who lost last week’s US Open after double-bogeying the final hole, was also only one behind with two to play but this time bogeyed the short 17th and by failing to birdie the 533-yard 18th had to settle for a share of fourth spot with another Dane, Thomas Bjorn.

His victory, worth £233,330, lifts Casey to fifth place in the Ryder Cup race and closes the gap on David Howell at the top of the Order of Merit.

But his joy was mixed with relief as he collected the trophy.

“It feels fantastic, more so because I had a couple of great players chasing me,” he said.

“To play with Colin in Scotland in the final group on a Sunday is a treat, very special, and it’s difficult when you have a guy like him breathing down your neck.

“But I had a great start (he birdied the first three holes) and battled through.”

Casey’s game was in tatters a year ago, an opening 85 at the US Open coming during a spell when he did not make a cut from April until August.

Many linked it to the impact his ill-chosen words about the Americans – “we properly hate them” – following his Ryder Cup debut had on him and he would not deny it was a tough time.

While he did his best to repair the damage done his game deserted him.

“I became paralysed over the ball and was beating myself up on the course. But all you can try to do is smile and battle through it,” he said.

“It wasn’t fun for a while – it can’t be when you don’t know where the ball’s going to go.”

Slowly and surely, with the help of American coach Peter Kostis, the pieces were put back together.

He won the China Open at the end of last year and since February he has finished no lower than 20th in any tournament.