Paul Casey grabbed a dramatic half point after a thrilling see-saw battle with Hunter Mahan.

The American was two up at one point and looked to have made the decisive move with a brilliant breaking birdie putt to win the 17th.

However, with the adrenaline pumping, he promptly fired his drive into the water at 18 allowing Casey to claim a share of the spoils with a fine birdie-four down the last.

A birdie at the first edged the Englishman ahead for the only time in the match, but Mahan was immediately on terms as his opponent then bogeyed the second.

Mahan moved in front with birdie at the fourth, while a par was good enough to double the lead at the next as Casey produced a clumsy pitch.

Casey halved the deficit with a tidy up and down at the seventh, but gave it straight back with another bogey at eight.

However, a former World Match Play champion, Casey showed his mettle with further birdies at nine and then 12 to haul himself level.

The match continued to sway one way and then the other as the Englishman fell behind again before getting back on terms with birdie at 16, but Mahan looked to have broken his opponent with his amazing 30-footer on the 17th.

But a fittingly dramatic climax followed at the last as Casey clinched a deserved half.