The Ryder Cup player's 12-under total of 132 left him alongside overnight joint-leader Brett Rumford, with Simon Khan and Angel Cabrera a shot behind.
"It was one of those fun days to play golf, an easy-going round where I never got in much trouble," said Donald, who will defend his European Masters title in Switzerland next week when qualifying for the 2006 Ryder Cup begins.
"I didn't think the course would suit me but the rough is a little thicker than it has been and it's wet because of all the rain, so accuracy off the tee is more of a factor than you would have thought." That plays into the 27-year-old's hands and he will be hoping he can turn a share of the lead into a first win of the season.
Donald's Ryder Cup team-mate David Howell is among a group of four players just two shots off the lead, the Swindon golfer three-putting the par-five ninth, his closing hole, for par in a round of 68.
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