Stricker's ace knocks Rory McIlroy off top spot

The Ulsterman, who had shared the first-round lead with American Chris Riley, finished his second in Dublin, Ohio, with the clubhouse lead after carding a level-par round to be six-under-par for the tournament.

However, Stricker came on strong and thanks to his later tee time stormed past the European Ryder Cup star to lead by three.

The hole-in-one was crucial for Stricker as a six-iron on the 188-yard eighth - he played the back nine first - found its way directly into the hole before a birdie on his last gave him a five-under round of 67.

The amazing finish saw him leap from a group of five sharing the lead to an outright advantage by three shots at the half-way point.

"It's a shock when you see that go in, obviously," Stricker, nine under overall on 135, said. "But in a good way! It was a great way to finish the round."

McIlroy, at 72, is level now with Ricky Barnes (70), Jonathan Byrd (67) and Australian Rod Pampling (66).

The 22-year-old picked up three bogies in his front nine but managed to pull shots back with birdies coming on the second, fifth and seventh.

A good back nine, in which he carded a further three birdies, was damaged by a double-bogey on the par-four 14th and another bogey on the 18th.

Britain's new world No.1 Luke Donald is five-under on 139 after a strong finish for a 69.