LAKE BUENA VISTA, October 20, 2011 - Britain's world number one fired a bogey-free six-under par 66 to head a group of seven players sharing the lead after the first round of the US PGA's season-ending $4.7 million Children's Miracle Network Hospitals Classic.
"Six birdies, no bogeys is always a good round," Donald said.
"I played a pretty solid round. Couple loose shots at the end. It wasn't that easy out there. The wind was strong enough to make it a little bit tricky with club selection."
Others opening on 66 on the Palm course were India's Arjun Atwal, Australian Nathan Green and Americans James Driscoll, Gary Woodland and Scott Stallings.
Derek Lameley carded a 66 on the other course in use for the first two rounds, the Magnolia.
"You would like to make your fair share of birdies and capitalize on the easier place," said Donald, who will play the Magnolia course on Friday. "I think I did that."
Donald leads second-place Rory McIlroy in the European Order of Merit by 1.6 million euros and was atop the US list until American Webb Simpson finished second last week to seize the money lead by $363,029 over Donald.
The Englishman can finish no worse than a two-way share of second this week in order to have a chance at the US PGA season money crown.
If Donald wins the top prize of $846,000, Simpson would have to finish alone in second for $507,600 in runner-up money to deny Donald the title.
If Donald finishes as the lone runner-up, Simpson must finish no worse than alone in eighth place, worth $145,700, to edge Donald. If Donald shares second for $413,600, Simpson needs at least a four-way share of 21st to stay on top.
Simpson, who has $6,200,243 to Donald's $5,837,214, fired a bogey-free 68, only two shots off the lead but in the tightly bunched field in a share of 15th place.
Simpson was playing alongside Donald in a morning group that started off the 10th tee.
Donald birdied the par-5 11th and par-3 12th holes, added another at the par-5 14th and birdied the 17th to stand four-under at the turn. He birdied the par-5 first and par-3 third then parred his way to the clubhouse.
Simpson had birdies on the par-5 11th, 14th and seventh holes and another at the par-4 fifth.
"He has played great all year and we've played a lot together towards the end of the year, so I was comfortable and I'm sure he was as well," Simpson said. "We fed off each other and played a good round."
Donald and Webb joked about their situation and money title duel at times during the round.
"He asked when I was having my off-season. I said, 'Well, it was going to be this week. Thanks for playing the last two weeks,'" Donald said.
"Just some lighthearted banter. That's fine. Not only do I have to beat Webb, I have to beat the rest of the field. I have to keep my eye on everyone."
In addition to being away from his wife, who is due to give birth in three weeks, Donald's decision to go for the US crown by playing this week kept him from a 10-year class reunion at Northwestern University near Chicago.
"I was meant to be the honorary captain at the football game, but hopefully I won't be missed too much," Donald said.