|Roger Federer, playing at Indian Wells in March, defeated Novak|
Djokovic 7-5, 6-2 in the round-robin phase of the ATP World Tour
Finals in London. Photo by Paul Bauman
It was Djokovic's first loss since he fell to Federer in the Cincinnati final in August.
Federer, 34, leads the head-to-head series 22-21. He and Djokovic have met more times than any other two players in the Open era except Djokovic and Rafael Nadal. The 29-year-old Spaniard leads the 28-year-old Serb 23-22.
Federer has beaten Djokovic in straight sets three times this year, but Djokovic is 4-3 against his rival this year, including victories in the Wimbledon and U.S. Open finals.
Federer, seeking his seventh ATP Finals title, improved to 2-0 in the Stan Smith group and qualified for Saturday's semifinals. Djokovic remains in contention for his fourth straight ATP Finals title and fifth overall at 1-1.
Djokovic, who came within one match of winning the first calendar-year Grand Slam since Rod Laver in 1969, dropped to 79-6 this year.
Top-seeded Bob Bryan and Mike Bryan also stayed in contention for their fifth ATP Finals title and second in a row with a straight-set victory.
The 37-year-old Bryans dismissed fifth-seeded Simone Bolelli and Fabio Fognini 6-3, 6-2 in round-robin play.
It was only the second victory since August for the Bryans, who failed to win a Grand Slam title this year for the first time since 2004.
The former NCAA champions from Stanford improved to 1-1 in the Ashe/Smith group and tied Daniel Nestor's record of 34 career doubles victories in the ATP Finals. Bolelli and Fognini, who won their first major title in the Australian Open in January, were eliminated at 0-2.
The Bryans lost their No. 1 ranking two weeks ago for the first time in almost three years. Their streak of six year-end top rankings also is in jeopardy.
ATP WORLD TOUR FINALS
Round-robin singlesKei Nishikori (8), Japan, def. Tomas Berdych (6), Czech Republic, 7-5, 3-6, 6-3.
Roger Federer (3), Switzerland, def. Novak Djokovic (1), Serbia, 7-5, 6-2.
(Sets record in parentheses)
Stan Smith group -- 1. Roger Federer 2-0 (4-0), 2. Novak Djokovic 1-1 (2-2), 3. Kei Nishikori 1-1 (2-3), 4. Tomas Berdych 0-2 (1-4).Ilie Nastase group -- 1. Rafael Nadal 1-0 (2-0), 2. Andy Murray 1-0 (2-0), 3. David Ferrer 0-1 (0-2), 4. Stan Wawrinka 0-1 (0-2).
Top two players in each group after three matches advance to Saturday's semifinals.
Round-robin doublesRohan Bopanna, India, and Florin Mergea (8), Romania, def. Jamie Murray, Great Britain, and John Peers (4), Australia, 6-3, 7-6 (5).
Bob Bryan and Mike Bryan (1), United States, def. Simone Bolelli and Fabio Fognini (5), Italy, 6-3, 6-2.
(Sets record in parentheses)Ashe/Smith group -- 1. Rohan Bopanna and Florin Mergea 2-0 (4-0), 2. Bob Bryan and Mike Bryan 1-1 (2-2). 3. Jamie Murray and John Peers 1-1 (2-3), 4. Simone Bolelli and Fabio Fognini 0-2 (1-4).
Fleming/McEnroe group -- 1. Jean-Julien Rojer and Horia Tecau 1-0 (2-0), 2. Ivan Dodig and Marcelo Melo 1-0 (2-1), 3. Pierre-Hugues Herbert and Nicolas Mahut 0-1 (1-2), 4. Marcin Matkowski and Nenad Zimonjic 0-1 (0-2).
Top two teams in each group after three matches advance to Saturday's semifinals.