Federer, earning a first-round bye as the No. 5 seed in Paris, opened the week in the lead among players yet to qualify for a spot in the Tour Finals in London. His 6-4, 6-4 victory Wednesday over Kevin Anderson gave him one of the berths.
Federer dropped his serve once -- when he was serving for the match at 5-2 of the second set -- but lost only 20 points in 10 games serving in earning the trip to London.
There are two spots remaining for the eight-player Tour Finals. Milos Raonic, seeded 10th in Paris, kept his slim hopes alive with a 6-3, 6-4 win over Robin Haase in the final second-round match. Raonic needs to reach the final in Paris for a chance to get to London.
Stanislas Wawrinka and Richard Gasquet are in the favored positions to claim the other two London spots. Wawrinka, the No. 7-seed at the Paris Masters, kept pace in the race with a 6-3, 3-6, 6-3 win Wednesday over Feliciano Lopez.
World No. 1 Rafael Nadal battled Marcel Granollers for 1 hour, 42 minutes before finishing off a 7-5, 7-5 win. Nadal won 80 percent of the points on serve but only managed one break against Granollers late in each set.
Third-seeded and defending champion David Ferrer topped Lukas Rosol 6-0, 2-6, 6-3. Ferrer had three breaks in each the first and third sets to advance. No. 4-seeded Juan Martin del Potro stopped Marin Cilic 6-4, 7-6 (7-3) and sixth-seeded Tomas Berdych beat Pablo Andujar 6-2, 7-5.