'I fooled them again, I guess,' said Doyle, who pocketed $470,000 for the win. 'It's a wonderful win, certainly. It makes the year. I won three majors and 10 tournaments. What a thing.'
Doyle smashed or tied several records on Sunday. The 63 matched Don Pooley's tournament record from 2002, but the 57-year-old obliterated Bruce Fleisher's 2001 mark for largest final-round comeback. Fleisher trailed by four when he went to victory, but Roberts and Craig Stadler were nine shots ahead of Doyle.
He missed the record for final-round comeback in major championship history by one. Paul Lawrie overcame a 10-stroke deficit when he won the 1999 British Open.
Weibring and Roberts both had their chances to win, but came up one short. Weibring shot a 1-under 70 and Roberts posted a 2-over 73 to come in at 9-under-par 275.
Greg Norman, in only his second event on the Champions Tour, carded a 2-under 69 and came in fourth place at 8-under-par 276. Tom Watson, last week's Senior British Open champion, managed an even-par 71 and shared fifth with Wayne Levi, who posted a 3-under 68. The duo finished at minus-7.
Doyle was already in the clubhouse at 10 under par, while Weibring soared up the leaderboard with three birdies in his first 10 holes. He played steady golf with pars and was one ahead of Doyle on the 17th tee.
Weibring drove into the left rough at the 17th, then came up short of the green with his second. He chipped to 6 feet, but missed the par putt left, tying him for the lead with Doyle at minus-10.
At the par-4 closing hole at NCR, Weibring found the rough again off the tee. He caught a flier lie and ran through the green with his second. Weibring knocked his chip 10 feet past the hole. He needed to hole the putt to possibly force a playoff, but he missed the putt right and now it was up to Roberts.
Roberts was alone in the lead at 12 under par after a birdie at the 10th, but things came crashing down quickly. He left a shot in the bunker at the 11th, then hurriedly blasted out to 25 feet, where he two-putted for double bogey.
His 4-iron tee ball at the par-3 13th found the front bunker and he could not save par. Roberts, who also made his debut on the elder circuit last week, was now at 9 under par and needed one birdie before he got into the clubhouse.
Roberts nearly holed a 40-footer for birdie at the 17th, but now needed a birdie at the last to force an extra session with Doyle. Roberts landed in the right rough with his drive, then played a smart second shot 35 feet left of the flag. 'The Boss of the Moss' never grazed the hole and the title went to Doyle.
Both of the runner-ups failed in their quest for their first major championships.
'It isn't a great feeling to finish bogey-bogey when you have a chance to win the U.S. Senior Open, but I've got to look at how I played all week, and it's just one of those things,' admitted Weibring. 'Congratulations to Allen Doyle.'
'I feel positive about the way I played because I'm going to tell myself, as poorly as I drove it on the weekend, I still had a chance to win the golf tournament,' said Roberts. 'That's the way I'm going to look at it, instead of looking at the fact that I threw the Open away.'
Doyle flew out of the gate on Sunday with a pair of birdies in his first three holes. He birdied the fifth, then drained a 6-footer for birdie at the sixth. Doyle birdied the seventh for three birdies in a row, but ran home a 20-footer for birdie at the eighth to make it four.
'You have to get on a run, which I did on the front nine when I birdied five, six, seven and eight,' said Doyle.
Doyle drained a 10-foot birdie putt at the 10th and added a birdie at 14 to reach 10 under par. He saved some great pars down the stretch, then watched as the leaders fell.
'I don't think you ever step up on the first tee with your goal being a 63,' said Doyle. 'How many times does that happen in an Open, when a guy gets in the clubhouse and the greens get a little firm? For it to happen to you is a great thing.'
Stadler also was in the mix until the par-4 ninth. His drive found a bunker and the ball landed near the lip. Stadler could do no better than a double bogey and that triggered a run of terrible golf for the third-round co-leader.
He bogeyed 11, 13, 14 and 15, then double bogeyed the 17th. Stadler birdied the 72nd hole to shoot a 5-over 76 and tie for seventh with Mark McNulty, who shot a 4-under 67. The duo came in at 6-under-par 278.
Des Smyth, who lost in a playoff to Watson at Royal Aberdeen last week, shot a 2-over 73 and tied for ninth place at minus-5 with Dana Quigley (69) and Rodger Davis (71).