Before today, he had succeeded less at this tournament than at the other three Grand Slams.
He beat Swiss Stanislas Wawrinka, who won against Gilles Simon, and who was his executioner last year in this same competition - winning in five sets from two sets down.
The Frenchman has several assets which could see him spring a surprise against world number one Novak Djokovic, but he must make changes to his approach.
He has an ego which keeps him free of self-doubt when things are going badly and his outlook allows him to find the best within himself at key moments.
His first-service ball is one of the most effective in the world and is coupled with a devastating drive shift. It is a sequence which he controls perfectly.
I am personally convinced that Tsonga has all the assets needed to shine on clay, even if, until now, that success has never come to the fore. Jo is a real attacker, and this surface has historically made such players hesitate in their natural game. The big question is always whether they must modify their game and adapt it to the surface, or impose their style upon it.
For me, there is only one answer to this question, the one that Edberg, McEnroe and Rafter gave in reaching the semi-finals or final of the Parisian tournament: excessive attack, without compromise.
If you look at Tsonga in this tournament, he hesitates between his punchy, powerful tennis and his 'Spanish' tennis style - heavy shots and the acceptance of the baseline fight. The second option forces Tsonga to play an unnatural game and he becomes tired, which leads to him giving up the baseline and causes him difficulties with his attack transition.
On the other hand, I am convinced that if he puts his excessive attacking game in place - leaning on his serve to be trenchant on the second shot, shifting to a drive when possible and going to the net - he will be efficient on clay. In return games, he must be aggressive on his opponent's second serves as much as possible, and use the volley return to put them under permanent pressure.
Sometimes, you have to accept a greater number of mistakes if the tactic is efficient in making the opponent's shots shorter.
The second problem for Jo is in his footwork. His base is not sufficient at the moment: he is often off-balance. Spreading his base and lowering by 20 degrees his centre of gravity would give him better stability. It would smooth out his mistakes on opponents' short balls and allow him to go forward easily. This is essential to the game he must adopt in the last eight.