Bruguera, the French Open champion for the last two years, held a running row with the umpire throughout the second set over a series of line calls that were given in Forget's favour.
Midway through the set in which both players held serve until the 10th game, the Spaniard stopped play and staged a brief sit-down protest.
'My concentration was broken in the first set by the line decisions which continued in the second. I was very angry but I cooled down later,' Bruguera said.
Bruguera's win, the 13th of his career, earned him dollars 65,000 ( pounds 42,000) while Forget collected dollars 38,200. It also enhanced his reputation as the best clay-court player on the men's circuit.
'I have never won three titles in a row and I am proud to be able to concentrate so well during a particular week,' Bruguera said.
It did not all go to plan as Bruguera lost the first set, dropping his service three times with a string of unforced errors.
A brief lapse in concentration by the 29-year-old Frenchman in the 11th game of the second set gave Bruguera a crucial break, enabling him to take it 7-5.
Bruguera, now in full flow, broke Forget's opening serve in the third set and broke him again in the seventh to take the set in 30 minutes.
The 23-year-old, ranked No 4 in the world, never looked back after breaking Forget again in the first game of the fourth, with further breaks in the fifth and seventh, to wrap up the match in just under three hours.
Forget, who was out of action with a knee injury for almost a year, continued his successful comeback. Two weeks ago he reached the quarter- finals at Wimbledon and his performance here as a wild card entry should see his world ranking rise from 1,130 to about 100.
'I am very pleased with my performance,' he said. 'Playing Sergi is like playing against a wall. The ball just keeps coming back.'
'I hope for some more wild cards so that I can move further up the rankings.'
Mark Petchey, the British player who was attempting to reach his first ATP Tour singles final, was beaten 4-6, 6-3, 6-4 by the American David Wheaton in the semi-finals of the Hall of Fame grass-court Championships in Newport, Rhode Island on Saturday.
Bernd Karbacher, the unseeded German, upset the Austrian holder, Horst Skoff, to win the Swedish Open clay- court tournament in Bastad yesterday. Karbacher, 26, won 6-4, 6-3 to win the second title of his career. For the first time since 1977, no Swedish player reached the semi- finals.Reuse content