LAKE BUENA VISTA, October 22, 2011 - Donald, the world number one from England, arrived here seeking to become the first player to win both the US and European tour money titles in the same season.
He came in trailing American Webb Simpson in the US standings, and his third-round 70 -- which included a double-bogey at the par-five 14th -- gave Simpson even more breathing room.
At the top of the leaderboard in the US tour's last official tournament of the year, Leonard chipped in three times to salvage a 70 for 14-under par 202 after three rounds.
He was joined by tour rookie Chappell, who fired a steady 66.
They were one shot in front of 21-year-old South Korean Bi-o Kim, who can secure his PGA Tour card for next year if he finishes no worse than a two-way tie for second.
Donald's duel with Simpson for the US money title was the main focus of the week, with the Englishman coming into the event trailing Simpson by $363,029.
"We’re both trying to play our best and see if we can win the golf tournament," said Simpson, a two-time winner on the tour this season. "There’s been a little added pressure but I think we’ve both handled it OK."
With four birdies in his first 12 holes, Donald was tied for fourth when he arrived at the 14th tee, three shots off the lead and three in front of Simpson.
By the time he'd hit into the water and three-putted for a double-bogey he was six shots off the pace and tied with Simpson.
The American finished with a 69 for 206, one shot ahead of Donald and now the favorite to take the money title.
"I'm a little more confident than I was two hours ago," said Simpson, who had four birdies on the back nine of the Magnolia Course.
"It was good to finish with four-under on the back," Simpson said. "I knew we were playing well. We just made a couple of mistakes we hadn’t made really this week at all, and it cost me a couple of shots. But other than that, it was a pretty good day."
Donald's three-putt from 34 feet at 14 ended a remarkable run of 483 holes without a three-putt.
"Yesterday I hit a dozen really poor shots, shot 71 and today I hit two really poor shots, but unfortunately they cost me and almost shot the same score," Donald said. "It's just the way golf is sometimes."
"The strength of my round was definitely from off the green," Leonard said with a smile. "I certainly didn't play great today, and to be able to hole ... really the two shots, at five and nine, from off the green certainly is a huge boost.
"There are days when those things don't go our way, and the round can get away from me."
Leading third-round scores here on Saturday at the US PGA Tour's $4.7 million tournament at Walt Disney World (USA unless noted):
202 - Kevin Chappell 70-66-66, Justin Leonard 69-63-70
203 - Bi-o Kim (KOR) 67-65-71
204 - Nick O'Hern (AUS) 68-66-70, Henrik Stenson (SWE) 68-64-72
205 - Kevin Kisner 69-69-67, Billy Mayfair 68-70-67, Tom Pernice 68-69-68
206 - Steven Bowditch (AUS) 67-71-68, Fabian Gomez (ARG) 73-67-66, Trevor Immelman (RSA) 72-68-66, Sunghoon Kang (KOR) 68-71-67, Webb Simpson 68-69-69
207 - Michael Bradley 72-69-66, Luke Donald (GBR) 66-71-70, Scott Gutschewski 67-71-69
...
208 - Greg Chalmers (AUS) 70-68-70, David Hearn (CAN) 71-67-70, Alexandre Rocha (BRA) 69-69-70
209 - Nathan Green (AUS) 66-71-72, John Senden (AUS) 70-70-69
210 - Ryuji Imada (JPN) 71-70-69
211 - Charlie Wi (KOR) 70-70-71
212 - Arjun Atwal (IND) 66-72-74, Jarrod Lyle (AUS) 68-72-72
217 - Retief Goosen (RSA) 68-72-77