The win was worth more to Fulke than just a $480,000 first-place check, it guarantees him a spot in next week's $5 million WGC-American Express Championship.
Meanwhile, the loss hit Clarke on two fronts. Not only was the Northern Irishman denied his third victory of the season, but he also missed a golden opportunity to distance himself from Lee Westwood in the money race.
Clarke's second-place finish was enough to supplant Westwood at the top of the Volvo Order of Merit. Clarke, who entered the week roughly $70,000 behind his good friend for first place in 2000 earnings, collected $333,500 for his runner-up effort. However, the Englishman fired back-to-back rounds of 65 over the weekend at Montecastillo to tie for third. With one official event remaining on the European schedule, Westwood is a mere $94,000 back of his stablemate.
'It is all going to come down to the last week,' said Clarke, who shot a final-round 68. 'I am a bit disappointed after going out tied for the lead not to win, but Pierre played fantastic down the stretch.'
Clarke, who began the final round tied with Fulke, led by one as the final twosome entered the par-5 16th. Clarke had played the final three holes in 7-under-par over the first three rounds, but it was Fulke who got the better of his playing companion on Sunday.
Fulke coaxed in a 25-foot eagle putt at the 16th to momentarily take the outright lead at 16-under-par, until Clarke dropped in a birdie of his own from eight feet.
Tied at the top, Clarke inexplicably hooked his tee shot at the par-4 17th deep into the left rough. Clarke was forced to lay-up from there and carded a bogey 5.
Now leading by one, Fulke had a chance to end the tournament with a 30-foot birdie at the 72nd hole - he narrowly missed. That gave Clarke a chance to force a playoff from 20 feet, which he was unable to do. Fulke then tapped in for par for a round of 5-under-par 67 and a one-shot victory.
Fulke, who was sidelined for five months due to a wrist injury, adds this title to the one he won earlier in the season at the Scottish PGA Championship.
'To have come back from the injury and play as well as I have is wonderful,' said Fulke, who moves from 31st to 12th on the money list. 'This opens a lot of doors.'
Aside from qualifying for the AmEx Championship, Fulke also leads the Ryder Cup points list.
Michael Campbell kept alive his hopes of capturing the money title by firing a 9-under-par 63 in the final round to tie Westwood for third place. The Kiwi stands in fifth place on the Order of Merit, some $680,000 back of Clarke.
Like Campbell, Colin Montgomerie is 'technically' in the hunt to record his eighth consecutive Order of Merit title. Monty carded a Sunday 65 to tie for ninth this week, and now finds himself nearly $840,000 removed from first place.
One million dollars is on offer to next week's winner in Valderrama, Spain. Both Montgomerie and Campbell must win and hope for a major collapse by, not only Clarke and Westwood, but also Ernie Els and Thomas Bjorn, who reside in third and fourth place, respectively, on the money list.