After both making par on the first playoff hole at the 18th, the pair moved to the 10th and while Cabrera failed to make a birdie, Scott made no such mistake as he holed from 15 feet to spark delirium.
Cabrera would have been the second oldest man to have won the tournament at the age of 43, with only Jack Nicklaus, who won at the age of 46 in 1986, ahead of him.
It would have been some achievement for the Argentine, currently ranked 269th in the world.
"That's how golf is," Cabrera, who hit a final round 70, said. "I came back. I had my chance to win it. Adam is truly a good winner.
"He's a great person and a great player and I'm happy for him."
Australia's Day was one of the first to congratulate Scott after he missed out on qualifying for the playoff -- eventually finishing two shots back on seven-under for the tournament.
"It was really tough," Day told reporters. "The pressure got to me a little bit."
While Scott celebrated, World No.1 Tiger Woods refused to blame his two shot penalty for taking an incorrect drop during his third round Saturday.
Woods finished with a final round of 70 to finish four shots off the lead -- but the U.S. star refrained from blaming Saturday's incident.
"We could do that 'what if?' in every tournament we lose," he told reporters.
"We lose more tournaments than we win out here on tour, so that's just part of the process and I'll go back to it.
"I thought 65 would win it outright today. I thought that was going to be the number and it looks like it was. If I would have shot my number, it might have been a different story.
"I had a tough time getting accustomed to the speed of the greens, they were so much slower than yesterday. I left every putt short on the first eight holes.
"I played well but unfortunately did not make enough putts and missed a few shots here and there. I had an opportunity today."
World No.2 Rory McIlroy carded a closing 69 to finish the week at two over par, but the Northern Irishman was satisfied with his game despite failing to challenge the leaders.
"I know I've played good enough golf here to win, it's just a matter of stringing it all together," McIlroy said.
"I was in a good position and did not quite have it all yesterday and that really cost me.
"You have to be right on your game for 72 holes here, I played a five hole stretch in five over and that was really it. I played nicely again today, if I just limit the mistakes from yesterday I am right there.
"It's frustrating. Sometimes you hit a good shot and all of a sudden it's off the green; it is what it is and you have to embrace it.
"It's Augusta and you're going to get some good bounces, you're going to get some bad. It will all even out in the end."