Federer faces early exit at ATP Finals after Thiem defeat squib

Roger Federer faces an uphill task to qualify for the last four of the ATP Finals after a 7-5, 7-5 defeat to Dominic Thiem in his tournament opener on Sunday. The six-time champion was in action in the evening match after Novak Djokovic had swatted aside debutant Matteo Berrettini in the earlier Group Bjorn Borg contest in London. Federer and Djokovic, who has won the end-of-season event five times, will meet later in the week in a repeat of this year's Wimbledon final, with two players advancing from the four-man group.
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