You just witnessed Jo-Willy's career in one point!
He had Gulbis on a string. Just toying with him. Then the hotdog took over. Two playful volleys, the second when Gulbis was sitting on his ass after a fall behind the baseline and well outside the alley. Two problems: (1) the second volley was supposed to 2 hop Gulbis and land on his face (who knows what Tsonga was thinking).
Instead, because Tsonga floated the volley in the corner of the court where Gulbis went down (rather that, say, anywhere else), Gulbis got up and won the point. Tsonga was laughing when the ball passed him.
(2) That point gave Gulbis set point. And Gulbis took the 2nd set.
What an idiot...