Ryder Cup star Chris DiMarco credited a return to his partnership with former caddie for the rediscovery of his form at the Open in Carnoustie.

The American carded a five-under-par 66 - the second best round of the week - to leap from two over to three under and right in contention heading into Sunday's final day.

Pat O'Bryan, bag man for seven years up until just over 12 months ago, is back carrying and DiMarco could not be happier.

"The difference is I have gone back to my old caddie," said the American, who last year had one of his in-laws Ryan Rue - a man with no professional experience - with him when he finished second in the Open at Hoylake.

As a result of that performance O'Bryan was dispensed with as Rue kept the job.

But the partnership has not worked out with DiMarco's winless streak stretching back to 2006 in the European Tour's Abu Dhabi Championship when, ironically, he had his wife Amy carrying the bag.

"We (he and O'Bryan) had seven years in the top 20 and before tournament last year I fired him," added the 38-year-old Florida-based New Yorker.

"I went to a guy I had to teach everything to and, to be honest, it got a bit of a burden. I don't have to do that with Pat.

"I went back to him three weeks ago and my thinking on the golf course is so much better. We have a lot of camaraderie together and it's a really good business relationship and he's a really good friend.

"I just think that I'm a different, more confident player with him on the bag."

That showed as, starting at two over, DiMarco had an outward half of 33 with four birdies and a bogey.

Three birdies and one bogey coming home thrust him right back into contention in a tournament he did so well in last year despite having been troubled by injury and losing his mother a couple of weeks before the tournament.

"I felt like I learned the strategy of the course the last couple of days," said DiMarco.

"I think yesterday's round (70) gave me a lot of confidence. I hit the ball the best I have done all year.

"I'm going to go out tomorrow and play aggressively, playing the course like I've been playing the course."