Published: Oct 28, 2011 9:19 AM EDT
Updated: Oct 29, 2011 6:30 AM EDT

SHANGHAI (AP) - U.S. Open champion Rory McIlroy shot a 3-under 69 on Friday to increase his lead to two strokes after the second round of the Shanghai Masters.

After opening with a bogey-free 64, McIlroy struggled on the front nine, bogeying the fourth hole and dropping two strokes on the par-4 ninth after driving into the water.

The 22-year-old star from Northern Ireland recovered with four birdies on the back nine to finish at 11-under 133 on Lake Malaren's Jack Nicklaus-designed Masters course.

Noh Seung-yul was second after a 63. The 20-year-old South Korea player began the round tied for 18th after an opening 72.

The 30 players are vying for the $2 million first prize, the richest in golf. All the top players are getting appearance money, and last place pays $25,000. Because the International Management Group-run event isn't sanctioned by a major tour, it doesn't have world-ranking points.