Schwartzel, 26, grabbed his first major title after yet another amazing day of high drama that saw Tiger Woods charge into a share of the lead and McIlroy, four shots clear overnight, collapse to an 80.
The 21-year-old’s suffering was the biggest last-day collapse in a major since Jean Van de Velde blew it from five clear at Carnoustie in 1999.
Three years before that, of course, Greg Norman was six in front at Augusta and with a nightmare 78 lost by five to Nick Faldo.
Now McIlroy’s name will, for the time being at least, be grouped with theirs. He finished only 15th, an incredible 10 shots behind.
In contrast, Schwartzel shot a best-of-the-day 66 to beat Adam Scott and Jason Day by two and their fellow Australian Geoff Ogilvy, Woods and England’s Luke Donald by four.
Schwartzel chipped in at the first, pitched in for an eagle at the third and then, behind once again after playing the next 11 in one over, closed with a staggering four successive birdies.
He got up and down from just over the 15th, made 15-footers on the next two greens and, with two putts for victory at the last, converted an 18-foot putt to end the week 14 under par.
“It was such an exciting day,” said Schwartzel, reflecting on a final round that saw the lead change hands no fewer than 15 times.
“There were so many roars and the atmosphere was just incredible. It was just a phenomenal day -- It was getting tight coming down the 15th and I needed to do something.”
A front nine 37 was bad enough for McIlroy, but such was his overnight advantage that he was still leading as he entered the famed inward half and endured horror upon horror.
First a triple bogey seven on the 10th, where his hooked drive hit a tree and rebounded in between the cabins way left of the fairway and not far from the tee.
He needed a wood for his third, went left again and then hit another tree with his pitch. Even with a bogey on the next he was still in it, but that was his first three-putt and at the short 12th, his mind seemingly scrambled, he four-putted for a double bogey and dropped another at the long 15th.
“I hit a poor tee shot on 10 and sort of unravelled from there,” he said, still looking shell-shocked minutes after signing a card he wished could be thrown away.
“I’m very disappointed at the minute and I’m sure I will be for the next few days, but I’ve got to take the positives -- I was leading for 63 holes. I will have plenty more chances I know and hopefully it will build a bit of character in me as well.
“I can’t really put my finger on it, but I lost a lot of confidence with my putting.”
For three days it had looked like McIlroy would becomes a major champion at a younger age than some of the greats of the game.
Although Woods got there before him -- by only eight months -- Jack Nicklaus and Seve Ballesteros were a year older when they broke through, Gary Player 23, Tom Watson 25, Arnold Palmer 28, Faldo and Sam Snead 30 and Ben Hogan 34.
Woods and Ogilvy threatened to stage the third biggest comeback in Masters history as they charged from seven back.It was Woods -- still without a victory for 17 months and now 21 events -- who first took the noise level up several notches. He birdied the second and third and then came back from a three-putt bogey at the short fourth with further birdies at the sixth and seventh and then a 10-foot eagle putt after two marvellous shots into the uphill 570-yard eighth.
A miraculous par save from pine straw and then a bunker at the ninth meant the opportunity was there for him to end his drought. But it was not to be. He three-putted again on the 12th, missing only from three feet, and missed a four-putt eagle effort he desperately needed three holes later.
Ogilvy joined him with a brilliant five successive birdies from the 12th and two closing putts, and then Donald chipped in at the last for 10 under as well -- and that after hitting the flagstick with his approach from the edge of the fairway bunker. Going in the water for a double bogey at the 12th when he was two behind was what he called the “killer blow,” adding: “It was probably my one bad swing -- a push with a nine-iron and I paid the penalty.”
Argentina’s 2009 winner Angel Cabrera and Korean KJ Choi held a share of top spot, but made costly mistakes.
So attention focused on the battle between Scott, Schwartzel and Day.
Scott led on his own when he birdied the 14th and a tee shot to 18 inches at the 16th moved him closer to becoming Australia’s first winner.
But while playing partner Day closed with two birdies, Scott parred them and well though he had played for a 67 -- Day shot 68 -- it was not enough.
So Schwartzel, a stablemate of McIlroy, proved to be the one who gave European Tour members their first-ever clean sweep of the majors.
