Andre Agassi captured his fourth ATP title of the year after a straight sets win over fellow American Jan-Michael Gambill in the Mercedes-Benz Cup final.

Agassi used his superior ground strokes to good effect as he retained his title in Los Angeles.

Agassi wrapped up the 6-2 6-4 win in one hour and 17 minutes when Gambill hit a forehand into the net.

"Right now I feel good about my game," said Agassi. "I need to keep bringing it."

But shortly after completing his win over Gambill, Agassi pulled out of this week's Canadian Tennis Masters due to a lower back and right hip injury.

His exit from the Toronto tournament led to him being hit with an $80,000 (�51,000) fine by the ATP Tour.

Lucky loser Kristian Pless of Denmark will take Agassi's place in the draw for Canada.

Agassi said: "I have had success at the events in Canada before and I regret not being able to take part this year in Toronto amongst a great field of players."

There were no signs of injury hours before as Agassi powered past Gambill.

The popular American conceded just five points on his serve in a 29-minute first set and had two service breaks in the second set.

"I can serve better and even get more aggressive," Agassi said.

"That's how I feel when everything is well within myself. I enjoy playing great matches - I'm playing better than ever.