Casey charge puts Tiger in shade

Casey, sixth on his Augusta debut in 2004, birdied the second, fifth, seventh and ninth for an outward 32.

The 30-year-old Englishman went eight under par and level with American Brandt Snedeker, who had earlier become the pacesetter on his own when South African Trevor Immelman bogeyed the short fourth.

Woods, meanwhile, was up into a tie for seventh place on four under, striking the ball beautifully and picking up strokes on the second, 10th and 13th.

Ian Poulter was the leading European at halfway, joint third with left-handers Phil Mickelson and Steve Flesch, and he reeled off seven pars in a row to remain five under and tied for fifth.

Twice champion Mickelson was alongside him, grabbing a birdie on the second with a marvellous pitch but bogeying the sixth after pulling his tee shot well wide of the green.

Lee Westwood was far from out of the hunt too, finding himself level with Woods after an outward 34. He three-putted the first, but birdied the second, sixth and eighth.

A week that promised so much for Justin Rose, meanwhile, took another turn for the worse after a thunderstorm held up play for 40 minutes.

Down from joint leader to 29th after a second-round 78 which went pear shaped with a triple bogey eight on the long 15th, Rose made another trip to the water in his third round.

This time it came with his wayward approach to the 505-yard par four 11th - the hole where fellow Englishman Nick Faldo won both his green jackets in play-offs.