McLaren said this week that his six-year alliance with the 37-year-old Englishman had simply "run its course" but may live to regret his move after Donald's third-round 65 put him firmly in contention for the first prize of $755,000.
The four-times Ryder Cup player, without a European Tour victory for three and a half years, showed his class when he reeled off six birdies in a sublime nine-hole run from the seventh to the 15th.
"The run-offs here just aren't in play at the moment because the greens are so soft," Donald told reporters after posting a nine-under-par tally of 204.
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"You can be more aggressive into the greens because even if you miss it and short-side yourself you can usually chip it close because of the soft conditions."
Donald, who has tumbled to 66th in the world after spending 56 weeks at the top of the rankings in four separate spells in 2011 and 2012, paid tribute to the home fans who have turned out at Woburn in their droves this week.
"It's always nice to play in front of great crowds like we've got this week," he said. "They've been very supportive.
"I would love to win any tournament but it would be a little more special coming here in the U.K.. It's been a little bit of a dry period for me, I haven't won for a couple of years but I would dearly love to get back in that winner's circle."
Lee Westwood, another former world number one, also put together his best round of the week when he carded a four-under 67 for a total of 206.
The highlight of the 42-year-old Englishman's round was a chip-in birdie at the par-five seventh.
(Editing by Ed Osmond)
