Amazing to witness so much determination, he's close to be K.O, even asked the chair umpire when was the next change, seems to have problems at the abs and legs, no breath, but still doing his best on the court.
Jo just talked about the difficulty to push (elevate/jump) with his leg after failing his serve at 4-6, because of a nerve feeling, feelsbad he tried his best but couldn't serve at this point.
Also Tsonga hitting good 1st and aces, the stamina could be an issue now
A real model for any athlete on the circuit.