Federer, the No. 3 seed, got by Denis Istomin 4-6, 6-3, 6-2. Federer dropped serve just once Wednesday and that was the difference in the first set. He didn't face a break point in the second set and saved all four Istomin's break chances in the third set.
It was announced that Tomas Berdych, who lost a first-round match Tuesday, nonetheless became the fifth player to get an invitation to the World Tour Finals. That leaves three spots open with Federer just ahead of Stanislas Wawrinka and Richard Gasquet, who both lost in the first round at Basel, and Jo-Wilfried Tsonga in the standings. Just 135 points separate Federer and Tsonga in the standings.
Back on the court, Ivan Dodig defeated sixth-seeded Kei Nishikori 6-1, 6-2 in a brisk 57 minutes. Dodig won 34-of-44 points on serve and 62 percent of the point overall in the rout.
Top-seeded and defending champion Juan Martin del Potro posted a 6-4, 6-4 win over Henri Laaksonen and No. 8-seeded Grigor Dimitrov beat Radek Stepanek but Michael Llodra eliminated Gasquet, who was seeded fifth, 6-4, 6-2 in first-round matches. The final first-round result saw Vasek Pospisil beat Robin Haase 6-4, 6-4.