Nadal dominated the first set, taking it in just 23 minutes.
Monfils settled into the match in the second set, initially taking a 3-0 lead. Although Nadal recouped the service break in the seventh game when Monfils netted a backhand, he couldn't bypass the Frenchman in the tiebreaker.
In the third set, Nadal broke Monfils in the fourth game when the Frenchman shipped two forehands long from 30-30.
He capped off his win by breaking serve again on a second match point in the final game when Monfils sailed a forehand long.