Roger Federer feels he has been more attacking with his return of serve this year and feels that helped him overcome Jo-Wilfried Tsonga in his opening ATP World Tour Finals match.
The world number four had lost to the Frenchman twice already in 2011, including a five-set thriller in the Wimbledon quarter-finals.
Federer start brightly at the O2 Arena, with the defending champion breaking in the fourth game of the first set before going on to take it 6-2. People
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