Nadal next faces fourth-seeded Briton Andy Murray, who rallied for a 4-6, 6-3, 6-4 win over Serbian Janko Tipsarevic.
After winning his first set comfortably, Nadal was within two points of victory in the second, but then the towering Tsonga began his brave resistance.
Tsonga broke — helped along by an untimely double-fault from Nadal — and then claimed the set with a magnificent forehand return winner.
The third set produced some highly entertaining tennis and the Frenchman combined explosive shots, deft slices and glorious backhand work around the net to stay in touch with the Spaniard.
Tsonga came close to breaking in the sixth game, but Nadal held his nerve and for all the ebbs and flows of what had become a real battle, the pair remained on serve until the ninth game
Nadal made the decisive break when Tsonga failed to keep a cross-court forehand in play and although the Frenchman staved off matchpoints, the second seed claimed the two hour, 49 minute contest when his opponent dumped another forehand into the net.
The Spaniard said he had made the mistake of playing defensively after he broke in the second set.
“Before that Jo had many more mistakes than usual and that made it less complicated for me. But when he started to play better I started to play defensively,” said Nadal, who expects another tough encounter against Murray.
“It is always hard against Andy. He is a player who pushes you all the way. I certainly need to make sure I recover well now,” he added.
“I drank very, very little the last two sets. I mean, must have been something to do with that. It was so hot and humid and to come off the court hydrated after not really drinking would probably suggest that I had drunk way too much.” — Reuters