Donald would become world number one for the first time if he wins this week
-10 L Donald (Eng) -9 Garrett Willis (US) -8 C Villegas (Col), J Furyk (US), J Day (Aus), C Campbell (US) -7 B Crane (US), I Poulter (Eng) Selected others: -5 G McDowell (NI) -4 K Na (US) -2 M Kuchar (US) Level B Davis (Eng) +5 R Fowler (US) +11 E Els (SA)
England's Luke Donald kept up his bid to become world number one by racing to a one-shot lead at the halfway stage of The Heritage event on the US PGA Tour.
Donald, who will overtake Lee Westwood and top-ranked Martin Kaymer if he wins, fired 65 to reach 10 under.
Garrett Willis (69) is second with Camilo Villegas (68), Jim Furyk (66), Chad Campbell and Jason Day (65) all eight under at Hilton Head Island.
Ian Poulter is one further back after a 66 at the Harbour Town course.
Donald, the world number three, will claim the top spot if he wins in South Carolina because Kaymer is taking the week off and Westwood is playing in the
which carries less ranking points.
The 33-year-old Donald, who
won the WGC Match Play
earlier this year and was tied fourth in the Masters, carded five birdies on his front nine at the Harbour Town course before dropping a shot at the 10th and picking up two more strokes at 11 and 15.
"I got off to a great start again, birdieing the first two holes gave me some good momentum," said Donald.
"I played that front nine really well. The back nine is a little bit tougher but, again, I did a lot of good things today, drove it reasonably well.
"Some of my misses were in good places where I could get a good up-and-down. It was a solid day."
And the Englishman admitted it was difficult to treat the tournament like any other with the world number one position up for grabs.
"I guess it's always in the back of your mind," he said. "It's hard to get away from knowing that with
and Facebook and the media and everything. You obviously know what's at stake.
"It would certainly be an honour and a great achievement to accomplish."