The two players finished level on 268, 16-under par and then, playing the 18th hole again, Westwood holed out from 25 feet for a birdie three. Jacobson, faced with a putt of some 20 feet to stay alive, trundled it inches to the right.
Westwood's victory, his fourth European Tour success of the year, earned him a cheque for pounds 66,660 and means that he is now only pounds 45,265.71 behind Colin Montgomerie in the race for the European No 1 spot, with only the Volvo Masters at Montecastillo, Spain, to come.
Jacobson, who shot 67 yesterday against 66 by Westwood, had ample consolation for he needed to finish in the top eight to save his Tour card and he did it in style, as well as collecting the second prize of pounds 44,440.
Westwood struck a killer blow at the 10th hole, where he holed a wedge shot from some 90 yards for an eagle two to join Jacobson and the New Zealander Greg Turner in the joint lead at that point, at 14-under.
Then Westwood went into the lead with a birdie at the 12th, Jacobson caught him with a birdie at the 15th and the Englishman regained the lead with a birdie two at the short 16th. Jacobson refused to quit and holed a long birdie putt at the 17th to draw level again and the leading pair both scored pars at the last.
Turner had lost his chance by dropping a shot at the 16th and had to be content with joint third place with another Swede, Robert Karlsson.
Colin Montgomerie deliberately missed the tournament this week because he felt he had a huge cushion at the top of the Order of Merit. But at his press conference, Westwood joked: "I hope Monty is looking forward to the Volvo Masters as much as he was at the start of the week.
"I said last Wednesday that I had come to Belgium with the intention of winning the tournament so it's great to do it. But all credit to Freddie Jacobson. To nearly win the tournament when you needed to finish in the top eight to save your tour card was a tremendous achievement."
Westwood felt that his eagle two at the 10th was only justice. "I holed out from 116 yards," he said, "but I missed from eight feet at the 9th and two feet at the 11th, so maybe I deserved a bit of luck.
"This week is the best I've played from tee to green and it's been a great year with four wins in Europe and one on the US Tour. If someone had offered me five wins at the start of the year, I would have taken their hand off."
Westwood is now looking forward to the Dunhill Cup at St Andrews next week and said: "I haven't played that well in my two previous appearances but I think England have a great team and we can win it."
He is partnering Peter Baker and David Carter and added: "I would like to be captain. It's a great honour to play for your country but it's an even greater honour to be captain as well."
Meanwhile in the Buick Challenge at Pine Mountain, Georgia, Fred Funk shot a four-under-par 68 to stay in front for the third day in succession, but saw his lead shrink to one stroke after three rounds. Funk started the day with a three-stroke lead and appeared ready to pull away with two quick birdies. But he played the final 16 holes at only two under for a score of 198. His round contained seven birdies and three bogeys.
Bill Glasson, who has played only nine events this year, carded a seven- under 65 to move into second place on 199. J L Lewis moved into third on 201 following a round of 66. Steve Elkington, of Australia also shot 66 and was level in fourth place on 202 with Steve Flesch.
Flesch is 35th on the US money list and needs a strong finish to be eligible for the season-ending Tour Championship, which is four events away and includes only the leading 30 money winners. Funk is 30th on 1998 winnings.
Davis Love III, the defending champion, posted his second consecutive 70 and was out of contention on 209.
Results, Order of Merit, Digest, page 26Reuse content