The winner last year at traditional Hamilton Golf and Country Club, Furyk had a 16-under 268 total on Angus Glen's links-style North Course. He earned $900,000 for his 13th PGA TOUR victory and first since last September in Ancaster.
And he guaranteed the name-starved event will have at least one top player next year at Glen Abbey.
'I'll be here,' Furyk said. 'I always think you should come back and defend a championship. ... I felt a lot of support out there.'
Three strokes behind Singh after the third round, Furyk birdied two of the first three holes -- holing a 35-foot putt on the par-5 first and a 9-footer on the par-4 third -- before moving ahead at 13 under with his third career ace.
'You dream of a start like that,' Furyk said.
Furyk used a 5-iron to attack the back-right pin position on No. 4, a hole he birdied the first three days. His ball landed in the fringe just over a large bunker and rolled about 30 feet straight into the hole.
'Tough pin on four,' Furyk said. 'To be able to fly a 5-iron back there on the fringe, have it release out and go in the hole is, obviously, a special bonus.'
While Furyk feasted on the long par 3, Singh had three bogeys and a par on the hole, eight strokes more than Furyk. On Sunday, Singh's tee shot went 25 yards right and he dropped a shot after taking two more strokes to reach the putting surface.
'Eight strokes, that's a huge turnaround on one hole,' Furyk said. 'It's pretty special to play the hole 5 under on the week. You usually do that on a par 5 and rarely or never see that on a par 3. A pretty darn good hole, too. It's not like a wedge or a 9-iron shot.'
Singh, the 2004 winner at Glen Abbey in a playoff with Canadian star Mike Weir, shot a 68. Ryan Palmer and George McNeill closed with 66s to tie for third at 13 under, and Bob Heintz (67) and Hunter Mahan (67) followed at 12 under.
Furyk took a two-stroke lead to the par-4 18th, but made it interesting by three-putting for a bogey. He missed a 5 1/2 -footer for par, giving Singh -- playing two groups behind -- a chance to force a playoff with a birdie.
'Obviously, 18 was a slip-up,' Furyk said. 'And playing maybe a touch conservative away from the pin. I thought I actually hit a pretty good little second putt. I thought it was going in and it leaked out on me. ... I'm glad it didn't cost me.'
With Furyk nervously sitting on the stairs behind the green, Singh hit his 165-yard approach shot about 20 feet over the pin.
'I knew he had a pretty tough putt,' Furyk said.
To Furyk's relief, Singh's bold putt ran 5 feet past the pin.
'I had my chances, but I couldn't get it going on the front nine,' Singh said. 'Jim played the front 4 or 5 under, so that's a big swing there. ... I had a chance on the last, but Jim played well. Anyone who shoots 7 under on the last day is deserving.'
Furyk followed the hole-in-one with five straight pars, then holed a 5-foot birdie putt on the par-4 10th to reach 14 under and take a two-stroke lead over Mahan and Palmer. The 2003 U.S. Open champion moved three shots ahead on the par-5 11th, two-putting from 30 feet for an easy birdie.
After Mahan birdied the 11th to pull within two strokes, Furyk -- after stepping away three times to further examine his line -- rolled in a delicate 8-footer on the par-4 12th for his third straight birdie and a three-shot lead.
Singh and Mahan cut Furyk's lead to two, but he pulled three ahead again with an up-and-down birdie on the par-5 15th. Furyk also scrambled for key par saves on Nos. 8 and 14 -- both par 3s -- and the par-4 16th after missing the greens in regulation.
With the comeback victory, Furyk became the first player to successfully defend a title in the event since Jim Ferrier won in 1950 and 1951. Sam Snead (1940-41), Leo Diegel (1924-25; 1928-29) and J. Douglas Edgar (1919-20) also accomplished the feat.
Because of the tournament's new position on the PGA TOUR schedule, Furyk probably would have taken the week off if he hadn't won last year. For most top players, the national championship wasn't a viable option because of its spot after the British Open and before the WGC-Bridgestone Invitational and PGA Championship. The third-ranked Furyk and No. 7 Singh were the only players in the top 35 in the field.
'I really appreciate all the support I had,' Furyk told the fans during the during the trophy presentation on the 18th green. 'It's been great coming to Canada the last two years. We'll see you next year.'
Furyk opened with rounds of 69, 66 and 69. ... Stephen Ames was the top Canadian, closing with a 69 to tie for 27th at 7 under. He's a naturalized citizen from Trinidad and Tobago. Weir shot a 71 to tie for 34th at 5 under. 'Today wasn't what I expected,' Weir said. 'I thought I was going to shoot a good score.' ... A Canadian flag topped the flagstick on the 18th green.