WENTWORTH, May 25, 2014 (AFP) - The Northern Irishman -- who announced his split from tennis star Caroline Wozniacki on the eve of the tournament -- fired a sparkling six-under-par 66, for an aggregate of 274, 14 under par, to win by a shot from Ireland's Shane Lowry.
Denmark's Thomas Bjorn surrendered a five-shot lead by the time he had got to the seventh tee after a disastrous seven on the sixth but still had a faint chance of victory after birdies at the 16th and 17th.
Bjorn, aiming for his 16th European Tour win, finished with a 75 and had to settle for a share of third place with England's Luke Donald with both finishing on 276, 12-under.
McIlroy said: "It been a weird week. When I got inside the ropes it was a little bit of release - it gives you four or five hours of serenity.
"I can't explain it -- it has been a week of very mixed emotions but I am sitting here looking at this trophy thinking 'how the hell did it happen?'"
McIlroy got his round going with an eagle three at the fourth but was knocked back by bogeys at the sixth and ninth before streaking home in 32.
He chipped in at the 10th for a two to go to 10-under and took the lead with a birdie at the 12th before successive birdie fours at the par-5 17th and 18th holes.
On the 18th he hit his second into a greenside bunker but chipped out to five feet and punched the air when he holed the putt.
- Record-equalling -
The 25-year-old has rarely performed well at Wentworth, having a previous best finish of fifth in 2009 and two missed cuts in the last two years.
He added: "I came in here knowing I was playing well. I have come here the last couple of years and I have been struggling with my game but I was excited to come here again because I knew my game was in good shape.
"I was looking forward to this week and it does my confidence the world of good being able to get the job done under pressure."
McIlroy's comeback from seven shots off the pace equals the record for this event after Simon Khan did a similar rescue job in 2010.
It is also the first time Mcilroy has won a European Tour event actually held in Europe.
Third-placed Donald paid tribute to his Ryder Cup team-mate and believes McIlroy's decision to make a clean and public break with Wozniacki may have helped him this week.
Donald said: "We all know what he has been going through and sometimes making those tough decisions can take a weight off your mind. He can engulf himself in the golf and he obviously played very well.
"He is at a place where he can't even make the cut usually but he goes on to win it - that's the beauty of the game."
Henrik Stenson boosted his chances of becoming world number one later in the day when he eagled the par-5 17th and finished on 280, eight-under-par, and in a tie for seventh.
The Swede had to wait until current number one Adam Scott had finished playing in the Colonial Invitational in Texas to see if he could overtake the Australian and Tiger Woods to claim the top spot.
Scotland's Stephen Gallacher surged up the board to finish in a tie for fifth alongside England's Simon Dyson, whilst Germany's Marcel Siem had a 68 to finish in a share of seventh with Stenson, South Africa's Thomas Aiken, Spaniard Pablo Larrazabal and Francesco Molinari from Italy.
Leading final scores from the European PGA Championship which finished here at Wentworth on Sunday (par 72)
274 - Rory McIlroy (NIR) 68-71-69-66
275 - Shane Lowry (IRL) 64-70-73-68
276 - Luke Donald (ENG) 71-67-68-70, Thomas Bjorn (DEN) 62-72-67-75
279 - Stephen Gallacher (SCO) 70-75-68-66, Simon Dyson (ENG) 69-74-69-67
280 - Marcel Siem (GER) 69-71-72-68, Henrik Stenson (SWE) 68-71-71-70, Thomas Aiken (RSA) 68-72-70-70, Francesco Molinari (ITA) 71-74-65-70, Pablo Larrazabal (ESP) 69-71-69-71
281 - Alexander Levy (FRA) 71-73-70-67, Martin Kaymer (GER) 68-75-69-69, Chris Doak (SCO) 69-72-69-71, Joost Luiten (NED) 70-71-67-73
282 - Marc Warren (SCO) 73-69-71-69, Richard Green (AUS) 70-73-70-69, Fabrizio Zanotti (PAR) 67-72-73-70, Rafa Cabrera-Bello (ESP) 65-73-73-71, Jonas Blixt (SWE) 68-71-72-71
283 - Paul Lawrie (SCO) 72-71-73-67, Chris Wood (ENG) 73-72-69-69, Seve Benson (ENG) 71-69-73-70, Eddie Pepperell (ENG) 69-73-68-73
284 - Justin Rose (ENG) 70-73-70-71
285 - Ian Poulter (ENG) 70-72-74-69, Mark Foster (ENG) 72-71-70-72, Andy Sullivan (ENG) 70-71-69-75, Anthony Wall (ENG) 67-76-67-75
286 - Romain Wattel (FRA) 72-74-73-67, George Coetzee (RSA) 75-70-70-71, Gregory Havret (FRA) 69-76-70-71, Anders Hansen (DEN) 71-69-74-72, Jamie Donaldson (WAL) 73-69-68-76