The 61 established a new course record at Hualalai Golf Club after Gil Morgan shot a 62 earlier in the round. Roberts' 25-under-par 191 total tied the lowest 54-hole score in Champions Tour history and the 25 under is the best score in relation to par in the history of the elder circuit.
'The scores were going so low all week,' said Roberts, who pocketed $290,000. 'You just have to keep your foot to the floor on this golf course. Fortunately, I made a lot of good putts coming into the house.'
Roberts collected his second win on the Champions Tour. He captured last year's Tradition and was an eight-time winner on the PGA Tour.
Don Pooley, the overnight leader, posted a 7-under 65 and finished alone in second place at 24-under-par 192. That also established a new Champions Tour record for lowest score to not win.
Jay Haas and D.A. Weibring both carded rounds of 9-under-par 63 on Sunday. They shared third place at minus-22.
Roberts was 3 under par for the day through seven holes, but found himself trailing. He birdied the ninth, then chipped in for eagle at the par-5 10th to reach 20 under par. Roberts was still one behind Weibring, who ran home an 18-foot birdie putt at the 12th.
At the 12th hole, Pooley sank a 25-foot birdie putt to join Weibring in first. Roberts, who played with Pooley on Sunday, rolled in a 16-footer of his own to make it a three-way tie for the top spot on the leaderboard.
Roberts got to 22 under par with a 9-foot birdie putt at the 13th. He kicked in a 4-footer for birdie at No. 14 to move one clear of Pooley. Weibring stopped making birdies and thus fell down the leaderboard.
Pooley drained a 10-foot birdie putt at the 15th to tie Roberts in first. Roberts converted an 18-footer for birdie at No. 16, but Pooley had a closer chance to draw even. His putt slid by on the left side, giving Roberts a one-shot lead with two to play.
Both competitors parred the 17th and both had birdie opportunities at the closing hole. Roberts had 30 feet, while Pooley was faced with a 19-footer.
Roberts took the excitement out of the climatic final hole. His birdie putt fell into the hole, and it was good that it did. Pooley rolled his birdie try in to finish one behind the record-setting champion.
'It was going a little too hard, but it went right in the back of the hole,' said Roberts, who will be one of Tom Lehman's assistant captains at this year's Ryder Cup. 'That was just icing on the cake. I couldn't have hit a better putt.'
Pooley made the turn at 1 under par, but six birdies on the back nine got him close. He conceded that it was hard to contend with your playing partner when he was shooting 61.
'Loren just played fantastic,' admitted Pooley. 'I'll get over it. I really wanted to win this, but Loren just played great.'
Morgan's 62 tied him for fifth place with Tom Watson, who only managed an 8-under-par 64 on Sunday. The pair came in at 20-under-par 196. David Eger also shot a 64 and finished alone in seventh at minus-19.
Tom Jenkins (64), Allen Doyle (66), Peter Jacobsen (67) and Jim Thorpe (68) shared eighth place at 15-under-par 201.
Dana Quigley, who won this title last year, carded a 6-under-par 66 and came in alone in 12th at minus-14.