The Czech world number six edged closer to becoming one of the eight players that take part in the end-of-season event with a 4-6 6-4 6-4 triumph over Tsonga on Sunday.
"London is always a goal every season," he said. "You have to play well the whole year to qualify.
"It will be special for me, if I make it for the third year in a row. I then hope to do well for Czech Republic in the Davis Cup final at home."
The ATP Finals start at the O2 Arena in London on November 5.