He lost his seventh final today
It seems he was injured according reports.
Benneteau started the match with his right forearm heavily taped, but he got off to the perfect start as he broke the Argentine's first serve.
Monaco broke back in the fourth and ninth games but Benneteau refused to give up and tied the first set 5-5.
The 12th game was a thriller that lasted 20 minutes and saw 12 deuces before Monaco broke Benneteau's serve to take the first set 7-5.
Benneteau, who looked uncomfortable throughout the match, called the trainer for attention to his right leg. But he came out strongly in the second set, breaking Monaco twice to take it 6-4.
However, it was Monaco who had the extra burst of energy in the third as he broke the Frenchman's serve in the sixth game to clinch the set 6-3, and with it the title.
"I was very focused on this game, because I wanted to win this final," said Benneteau, who was also a beaten finalist in Sydney in January.
"The fans were great, there was a lot of French in the crowd. It was a nice atmosphere and the game was a good level.