'It feels fantastic. I've been waiting for this win for many years,' said Jacquelin. 'I've tried hard and I've worked hard on it and its just fantastic that the work paid off.'
Jacquelin tied or set several records on the week, but none are official as lift, clean and place rules were in effect. The Frenchman's total of 261 would have bested the tournament record of 264 set by Retief Goosen and Steve Webster in 2001.
Previously, he had tied the 36-hole mark of 128 and his three-round total of 192 tied the tour record and set the event mark. That three-round total matched the European Tour record set by Tiger Woods five years ago, and was four strokes better than the tournament mark of 196. That record was set by Goosen in 2001.
Paul Lawrie, the 1999 British Open winner, took second place at 20-under-par 264 thanks to a final-round 64. Anders Hansen also shot 7-under 64 to share third place at 18-under-par 266 with Darren Clarke. European Ryder Cup captain Ian Woosnam finish in fifth place at 17-under-par 267 after a 65 on Sunday.
Jacquelin got off to a steady start with three straight pars. He two-putted for birdie on the par-5 fourth to move to 22 under. He led by six at Club de Campo, but his lead would shrink quickly.
The Frenchman missed the green at the par-4 eighth and he was unable to save par and his lead quickly was cut to three strokes as Lawrie had climbed to 18 under.
'Even more difficult,' Jacquelin said of when his advantage dropped to three strokes after eight holes. 'I tried to hang on and get some chances for birdie. I missed a lot of putts, but I saw Paul doing the same.'
Lawrie birdied two, four and six to get to 16 under. He then birdied the eighth and chipped-in for birdie on No. 9 to move to minus-18.
Jacquelin birdied the 11th when he drained a 12-foot putt to go four up on Lawrie. The Scotsman, playing one group ahead of Jacquelin, birdied 12 to get back within three.
The 33-year-old Jacquelin got up and down for birdie on the par-5 14th to move to 23 under. Lawrie closed back within in three with a birdie on 15.
Jacquelin scrambled to pars on his way in. He two-putted for par on 15, then got up and down for par at the next. He two-putted 17 for par and did the same at the last to hang on for the first win of his 10-year career.
'It was tough today,' Jacquelin said. 'I stayed relaxed and had a few jokes with my caddie. That helped me not think about the win. I did my best and today my best was a 69. I thought I had won on 17, but not before.'
Lawrie could not put more pressure on Jacquelin, as he parred the last three holes to take second place.
'Someone had to have a go, but Raphael had to make a few mistakes for me to have any chance, so good luck to him,' Lawrie said. 'He was so far ahead, second place seems like winning.'
Jose Manuel Lara fired a 7-under 64 to climb into a tie for sixth at 16-under-par 268. He was joined there by Jose-Filipe Lima, who closed with a 69.
David Lynn and European Tour Order of Merit leader Colin Montgomerie tied for eighth at minus-15 with Gregory Bourdy. Miguel Angel Jimenez was one stroke further back at 14-under-par 270 after a final-round 68.