Casey fired nine birdies and an eagle to take himself to 19-under for the tournament, two ahead of nearest challengers Alex Cejka and Australia's Stephen Leaney.

German Cejka equalled Rodger Davis previous course record with a 63 while Leaney carded a 66.

Ryder Cup vice-captain Ian Woosnam made a 68 to lie joint fourth on 16-under alongside Worthing's Gary Evans who hit a 65 on a day of low scoring.

Casey, European Tour rookie of the year in 2001, was in contention for one of the Ryder Cup wild cards eventually handed to Sergio Garcia and Jesper Parnevik by captain Sam Torrance.

"It was very nice of Sam to say what he did and earlier this year while I was playing average golf it was almost embarrassing," he said.

"You feel like you have let him down.

"It's nice to shoot some low numbers and show everybody what he saw in me last year. Making the team in two years time is now the goal."

Casey made six birdies in his first seven holes to storm to the turn in 30, and recovered from a bogey on the 10th to card three more birdies and an eagle on the closing stretch.

Leaney would have held outright second but for dropping his first shot of the week on the 18th, the 33-year-old finding a bad lie in the rough to the right of the fairway.

Of the eight Ryder Cup players who survived the halfway cut, veteran German Bernhard Langer was the best placed on 12 under after a 66.

Scotland's Colin Montgomerie was one behind after a 68, while Pierre Fulke was 10 under after a 66 alongside Padraig Harrington.

Thomas Bjorn carded a 70 to lie nine under, Lee Westwood fell back with a 73 after two of his best rounds in a long time on the opening two days, Paul McGinley signed for a 71 and Niclas Fasth a 75.

Montgomerie said he was still working on his putting, but said he was encouraged by his form.

"I am too far behind (to win) but a good round on Sunday and that would be a very positive week," he said.