Padraig Harrington admits he is nowhere near the level that saw him raise the Claret Jug at Carnoustie but he concedes the WGC Bridgestone Invitational in Akron, Ohio is excellent preparation for next week's US PGA Championship.

Testing conditions and a demanding set-up at the Firestone Country Club have made the £4 million event, led at the halfway stage by South Africa's Rory Sabbatini on six under par, the ideal tune-up for next week's final major of the season at Southern Hills in Tulsa, Oklahoma.

Having taken a week off to celebrate his victory at Carnoustie, Harrington came into the Bridgestone Invitational knowing he would be working hard to rediscover his winning touch in time for the US PGA after a week dominated by media commitments.

And playing an already tough course beefed up with narrow fairways, major-like rough and hard, fast greens, Firestone has proved the perfect place to hone his skills once again.

"That's what's keeping me going out there this week," Harrington admitted following his second-round 69, just one of 11 sub-par rounds on a trying day.

"I'm not hitting the ball as well as I would want to but I know with the PGA coming around next week I've got to stay in there and work hard.  This could be a major championship course, no doubt about that.

"Certainly the fairways are as narrow as we see, the rough is as heavy. It definitely helps."

Harrington lies in a tie for 15th place on one over heading into the third round, seven shots adrift of Sabbatini and one behind Ryder Cup team-mate Paul Casey, who agreed with the Irishman about the Firestone set-up.

"We could just stay here and play this course again," Casey joked. "This is a major set-up and we could stay and play and it will be a bit cooler than next week. That would be the advantage.

"I think it's fantastic preparation for a major championship. It was always a nice location in the season and you felt in the past it was a bit relaxed after a major championship but you flip it this side of a Major and it's great. It really is. There's no better golf course to get your game in shape and be prepared for next week."

Masters champion Zach Johnson lies in second place at Firestone, two shots back of Sabbatini on four under following a round of 65, the joint-lowest of the day alongside Davis Love III.  PA