It was the 11th career tournament title for the 29-year old Chilean defending champion.
"I think I've played some of the best matches in my career here and I am happy this happened in my country," said Gonzalez.
"The crowd was great and I thank them for a wonderful support. I think they are always a major headache for my rivals here," he added. "This is like a romance between me and the fans."
After a smooth first set for Gonzalez, Acasuso showed a reaction in the second set.
With the second set at 3-3, Gonzalez broke Acasuso's serve and then took advantage of a double fault by the Argentine to move ahead 5-3. He then held his serve to win the set and the match.
"I thank 'Chucho' Acasuso for letting me win at home," Gonzalez joked. "But seriously, he is good friend, a great player and a great human being."
Acasuso, the 2006 champion here, lamented that "I couldn't show my best tennis here this time."
Gonzalez is 8-2 against Acasuso.