Jacquelin made four bogeys on his last six holes but closed out his second European Tour title anyway with a 1-over 73, hanging on for a two-shot win over Denmark's Soren Kjeldsen.
'It is a fantastic moment,' said Jacquelin, who finished at 10-under 278.
Kjeldsen also had a 73 and finished alone in second place at 8-under 280. He made a double-bogey at the 14th and a bogey at he 16th, one of a handful of players who made the win easier for Jacquelin.
'But second (place) on my own is good,' he contested. 'I have not played that great this year and this gives me a lot of confidence.'
Asian Tour regulars Simon Yates (74) and Scott Hend (75) tied for third place at 7-under 281, while 2005 champion and world No. 5 Ernie Els (72) shared fifth place with Richard Sterne (69), Sung-Man Lee (73) and Markus Brier (74) at 6-under 282.
Scoring was considerably higher Sunday than it had been in the first three rounds, but you couldn't tell by looking at the champion's scorecard early on.
Jacquelin, who carried a one-shot lead into the final round, birdied No. 1 to extend his advantage. Further birdies at Nos. 6 and 8 moved him to 14 under, where he made the turn with a four-shot lead on Kjeldsen.
His lead dipped to three shots (over Hend) with a bogey at the 13th, a hole he birdied in each of the first three rounds. But even after another bogey at the 14th, his lead remained three shots.
Jacquelin's advantage was finally trimmed to two shots when he bogeyed the 17th, where it would remain even after a closing bogey at the 18th.
The mini-collapse was irrelevant because Kjeldsen, Yates and Hend played the final five holes a combined 8 over par.
A windy, rainy Tomson Shanghai Pudong Golf Club was tough on just about everyone -- especially down the stretch.
'The wind picked up and the rain and it was tough from the 12th to the 18th,' said Jacquelin. 'My shots were not so good, so I played for the good side of the green and tried to save par.'
The win represents Jacquelin's third strong showing in as many weeks.
It began with a runner-up finish in Portugal to surprising amateur Pablo Martin-Benavides, then continued last week at the China Open, where he held the 36-hole lead only to finish tied for sixth.
Jacquelin's 54-hole lead this weekend ranked as just his second on the European Tour. In his only other win -- at the 2005 Madrid Open -- he carried a seven-shot lead into the final round.
'When you are in a position to win it is always difficult to finish, but to be a winner you have to finish,' he said. 'It is my second win so it is not a surprise any more.'
Further down the leaderboard, several of the biggest names in the tournament posted commendable finishes.
Miguel Angel Jimenez had a 73 Sunday and finished in a five-way tie for 10th place at 4-under 284.
World No. 8 Retief Goosen closed with a 71 and tied for 15th place alongside eight-time Order of Merit champion Colin Montgomerie (77) and two others at 3-under 285.