SINGAPORE, May 4, 2014 (AFP) - Aguilar fired eight birdies in a sensational final round but he was still trailing Denmark's Hansen by a stroke when he stepped onto the 18th tee at the par-72 Laguna National Golf and Country Club.
But he heroically holed out with a pitching wedge for a two on the par-four final hole. His 10-under-par 62 gave him an aggregate score of 22-under 266, one better than Hansen who shot 67 to finish joint second with American David Lipsky.
The eagle at the last completed a jaw-dropping back nine in which Aguilar picked up eight strokes, including four birdies in a row from 10 plus two more on 15 and 17.
The 39-year-old, who started the day four shots back in shared seventh, had rounds of 65, 67, 72 and 62 for his second European Tour victory after he won the Indonesian Open in 2008.
"Yesterday I thought I had no chance," said Aguilar, who admitted he "got a bit lucky" on the last hole.
"Today I said to my caddie on the 17th after I made a birdie if we can make a birdie on 18 we can out some pressure on the leader and he said, 'What about making a two?'
"I said to him, the way I had been hitting the ball I could well do. It's a long story but I made two on 18, and what a beautiful way to finish."
Aguilar dashed Hansen's hopes of a fourth European Tour win, while Thailand's Panuphol Pittayarat, the joint overnight leader alongside Hansen, crashed to a 74 which gave him a share of 11th.
India's Rahil Gangjee was three shots back in fourth and England's Chris Wood was fifth. India's Anirban Lahiri and France's Gregory Bourdy were tied for sixth in the $1.5 million, co-sanctioned event.
The tournament was held as the Ballantine's Championship in South Korea for six editions from 2008, but after losing its title sponsor it was hurriedly relocated to Singapore last month.
Leading round-four scores from The Championship, co-sanctioned by the European and Asian Tours, at Singapore's Laguna National Golf and Country Club (par-72) on Sunday:
266 - Felipe Aguilar (CHI) 65-67-72-62
267 - David Lipsky (USA) 64-68-70-65, Anders Hansen (DEN) 67-66-67-67
269 - Rahil Gangjee (IND) 66-67-71-65
270 - Chris Wood (ENG) 68-67-68-67
271 - Anirban Lahiri (IND) 67-70-68-66, Gregory Bourdy (FRA) 66-70-67-68
273 - David Drysdale (SCO) 68-70-70-65, Raphael Jacquelin (FRA) 69-70-68-66, Tommy Fleetwood (ENG) 68-67-69-69
274 - Rikard Karlberg (SWE) 70-68-70-66, S.S.P. Chowrasia (IND) 68-68-71-67, Antonio Lascuna (PHI) 68-69-69-68, Baek Seuk-Hyun (KOR) 66-67-72-69, Terry Pilkadaris (AUS) 68-70-66-70, Panuphol Pittayarat (THA) 63-68-69-74