Spanish star Sergio Garcia has surged up the boards to take the lead after the second round of the US PGA tours penultimate playoff event as Adam Scott tried to rescue a floundering Australian tilt.

Garcia fired a six under par 64 at the BMW Championship at Cherry Hills Country Club to rocket up to eight-under overall, opening up a one-shot lead over American Ryan Palmer.

Palmer matched Garcia’s 64 to ensure he sits second alone while world No.1 Rory McIlroy carded his second straight 67 tie for third with the United States’ Billy Horschel (66) at six-under.

Adam Scott came home with a wet sail to shoot a 66 and rescue the Australian tilt, sitting five off the pace in a tie for eighth at three-under.

Scott rode a rollercoaster of birdies and bogeys on his opening nine with three of each before four birdies in his last nine allowed the Queenslander a glimmer of hope with two rounds remaining.

John Senden also provided a small spark with a 66 of his own but at one-under for the tournament, he remains a distant seven shots off the pace.

The remaining Australians are well back and need miracles to compete over the weekend.

Jason Day, who struggled with a back complaint in the opening round but had been cleared of any serious issues via an MRI, was nonetheless unable to continue after nine holes and withdrew from the event.

The lower back strain continued to bother him on Friday and the Queenslander pulled the pin after hitting his approach on the ninth hole.

He had been struggling at three-over on his round and decided to try to protect himself for next week’s season-ending tour championship, although his participation at East Lake is still uncertain.

“I am extremely disappointed to have to pull out of this event,” Day said.

“I will be getting treatment over the next few days and hopefully be ready for the Tour Championship.”

Geoff Ogilvy (69) and Stuart Appleby (71) are so far protecting their place in the tour championship next week but, at two-over in a tie for 34th, will need to keep pace over the weekend.

The season is all but over for Marc Leishman (+3), Matt Jones (+6) and Steven Bowditch (+9) as they needed to finish inside the top four to advance.