Federer is in position to claim the season-ending tournament for a record sixth time, and figures to have the upper hand. He owns a 7-3 record against Tsonga all-time, including 5-2 in 2011, and beat the Frenchman earlier this week in group play.
Moreover, Federer seems unstoppable at the moment. The Swiss superstar went unbeaten in three matches during round-robin play this week to win Group B, and has won 16 straight matches dating back to a loss to Novak Djokovic in the semifinals of the U.S. Open.
After a couple of Davis Cup wins in September, Federer won titles at the Swiss Indoors and Paris Masters earlier this month prior to this week's run. He beat Tsonga in the final in Paris.
Tsonga, however, topped Federer in the quarterfinals at Wimbledon and in the Montreal Masters. He has also played well late in the season, taking the Metz title in September and the Vienna crown in late October.
He moved into Sunday's final with a dominant victory against Berdych. Tsonga used his serve to control the match, firing seven aces and winning 90 percent of his first-serve points. He also won most of the points when forced to go to his second serve, and was broken just once.
Berdych had won the only previous match between the two, but committed 13 unforced errors in the first set Saturday and never recovered.
Tsonga's serve will have to be in good form Sunday against Federer, whose service game improved against Ferrer.
After he broke Ferrer's serve in the 11th game of the first set, Federer held at love to win it. A break of serve to start the second set was all Federer needed and he wrapped up the match with another break to close it out.
Ferrer won just one point against Federer's serve in the second set and did not manage a single break-point chance during the match. He dropped to 0-12 lifetime against Federer, including a loss in the final of this event four years ago when it was held in Shanghai.
Federer will try for his 70th career title and fourth this year against Tsonga. He won the season-opening event in Qatar before enduring a lengthy dry spell that finally ended with the triumph in his native Basel to start the month of November.
In addition, he will now finish the year ranked in the top three for a ninth straight season.
Another win on Sunday would also give Federer his 39th career victory in the Tour Finals, tying him for the most all-time with Ivan Lendl. He would also surpass Lendl and Pete Sampras for the most titles in the season-ending event.
Federer joined Jimmy Connors (163), Lendl (146), John McEnroe (108) and Guillermo Vilas (104) as the only players in the Open Era (1968) to reach 100 Tour-level finals, and Saturday's win was the 806th of his career to match Stefan Edberg for sixth-most in the Open Era.