The Czech world number six had lost all three of his matches in the capital this year, going out in the first round at Wimbledon and the Olympics and losing his opener to Andy Murray at the O2 Arena on Monday.
But he recovered impressively from dropping the second set on Wednesday night to race through the decider and secure a 7-5 3-6 6-1 victory.
A Tsonga win would have sent Novak Djokovic, a three-set winner over Murray earlier, through to the semi-finals and eliminated Berdych, but Wednesday night's result means nothing has yet been decided.
This was Berdych and Tsonga's third meeting in a month after clashes in Shanghai and Stockholm, both of which were won by the Czech.
He looked like he may have blown his chance in the first set when he missed a simple volley on break point in the seventh game, but made amends in the 11th game and served it out.
Tsonga, who lost to Roger Federer in last year's final, was staring at the exit door as a straight-sets defeat would have seen him eliminated on Wednesday night but he hit back and broke for a 3-1 lead in the fourth game of the second set.
The popular Frenchman then saved a break point on his way to serving out the set, and had two chances to break Berdych in the opening game of the decider but it was the Czech's turn to dig in.
That proved to be a crucial moment as Berdych broke in the fourth game and polished off victory in an hour and 52 minutes with his fifth game in a row.