Roberts birdied three of his last four holes in regulation to close a round of 5-under 67 and join Quigley at 15-under-par 273. Quigley birdied 15, then eagled 16th, but bogeyed 17 and parred 18 to end a round of 4-under 68.
At the first extra hole, No. 18, both players split the fairway with their tee shots. Roberts landed on the green some 18 feet from the cup. Quigley lost his second shot right of the green in a bunker on the South Course at The Reserve Vineyards & Golf Club.
Quigley, who leads the Champions Tour money list this season, hit a stellar bunker shot to 2 feet. Roberts' eagle putt stopped just inside Quigley's mark.
Both Quigley and Roberts kicked in their short birdie putts. On the second playoff hole, the par-4 17th, Roberts' tee shot missed the fairway right, while Quigley found the short grass.
Roberts second shot from the rough bounced well long onto the adjoining 11th green. Quigley's second shot landed on the green, but bounced hard and ran into the rough next to a greenside bunker.
The 50-year-old Roberts pitched from 162 feet to about 15 feet. Quigley, with a very difficult stance, pitched his to 14 feet. Roberts par putt rolled some 3 feet past the cup.
Quigley, who also lost in a playoff at the Senior PGA Championship, pulled his putt left of the cup, 4 feet by. His bogey putt lipped out the left edge and he tapped in for double bogey. Roberts tapped his short bogey putt in for the win.
'I hit such a great second shot here at 18 and then Dana hit that great bunker shot,' Roberts said. 'You get to 17 and anything can happen. Unfortunately, neither of us played the hole very well, but I feel bad for Dana that he finished that way.'
Gil Morgan, who shared the third-round lead with Doug Tewell, posted a 1-under 71 to finish one shot out of a playoff at 14-under-par 274. Mark James rallied late to shoot 4-under 68 and end at minus-13.
Tewell struggled to a 1-over 73 to came in at 12-under-par 276. He was joined there by Tom Jenkins (72) and James Mason (67).
Roberts got into red figures on Sunday with a birdie on the par-4 third. He came back two holes later with another birdie to move to 12 under par.
The eight-time winner on the PGA Tour parred his next nine holes. Roberts got up and down for birdie on the par-5 15th. He nearly lost the tournament at the 16th when his second shot found water near the green.
Roberts, however, got up and down to save his par. He moved within one of Quigley with a birdie on the 17th. Roberts again got up and down for birdie at the last to force the extra session.
'It was a good par on 16 and 17 was key,' said Roberts. 'I got to make that putt to even have a chance. Those putts on 17 and 18 were the two best putts I hit all week and they came at the right time. I'm delighted with the way I finished. I finally finished a round off.'
Quigley played the front nine at minus-2 with birdies on one and six. Around the turn, he dropped a shot at the 10th as he three-putted for bogey. That dropped him into a five-way tie for the lead.
The 58-year-old Quigley got that stroke back with a 6-foot birdie putt on 12 that gave him a one-shot cushion. After a pair of pars, got up and down for birdie on the 15th to move to minus-14.
Quigley then rolled in a 10-foot eagle putt on 16 to jump three clear of the field. However, his tee shot found thick rough right of the fairway at 17 and he was forced to pitch out. Quigley walked away with a two-putt bogey and parred the last to join Roberts in the extra session.
'I'm over the tournament already if you can believe it or not,' said Quigley. 'I'm not going to have a negative thought about what happened out there. I'm just really, really pleased with the way I've played. I continue to surprise myself with the fact that I'm in contention in these big tournaments.'
Mark McNulty finished alone in eighth place at 11-under-par 277.
Senior PGA champion Mike Reid (68) and Senior British Open winner Tom Watson (66) climbed into a tie for ninth place at 7-under-par 281. They were joined there by D.A. Weibring and R.W. Eaks.