A brilliant second-round eight-under 64 on Friday gave Swede Peter Hanson a two-shot lead over world No 1 Rory McIlroy at the halfway stage of the BMW Masters in Shanghai.

McIlroy turned on the style, yet still could not catch his Ryder Cup teammate at Lake Malaren Golf Club.

Overnight leader Jamie Donaldson of Wales started the day four strokes clear, but followed his course record 62 with a 74 to fall six behind.

McIlroy carded seven birdies on his way to a 65 that lifted him to 12 under, but 35-year-old Hanson produced nine as he reached 14 under par.

They have opened up a gap on the rest of the star-studded field. Hanson's compatriot, Robert Karlsson, is three strokes further back in third after he also shot a 64 to burst out of the pack.

Hanson began his day's work with a bogey. But then came a brilliant display of iron play as he birdied the long third and then struck an approach to four feet at the fifth to spark a run of four birdies in succession.

Having turned in 32, he holed a six footer for birdie at the 11th, holed from half that distance at the short 12th after a magnificent tee shot, chipped to two feet at the next hole, and then let his putter do the work on the 15th as he rolled in a 20 footer.

"It's amazing how many good rounds come together after a bogey on the first," Hanson said.

"It's pretty soft, so you can see yourself shooting some low scores here. I'm happy with the way I have played so far and I know it's going to be a tough one coming up against the world No 1 these last couple of days on a golf course he obviously loves. He won here last year."

The five-time European Tour winner now faces a head-to-head battle with a player who won the Shanghai Masters on the same Lake Malaren course 12 months ago and is seeking his fifth victory of the season.

McIlroy turned in 32, picking up shots at the second, third, eighth and ninth, and then had a hat-trick of birdies from the 13th on another day of low scoring.

"It was a very good day," said the US PGA champion. "I played very well - a little better than I did yesterday. I hit the ball a lot better and gave myself plenty of opportunities."

Y.E. Yang of South Korea carded the BMW Masters' first hole-in-one at the sixth hole and won a bottle of champagne.