London, England – Defending champion Roger Federer set ending $3.5 million ATP World Tour Finals.
Federer had already secured a berth in the semifinals coming into Thursday's match and he sits atop Group B after winning all three matches here thus far, dropping just two sets in the process.
Coming off his thrilling rout of Rafael Nadal on Tuesday, Thursday saw the Swiss Federer down Fish, who had already been eliminated from the semifinals, 6-1, 3-6, 6-3, for his 37th victory at the Tour Finals.
That places Federer in second place on the all-time list ahead of Boris Becker, and just two wins back of leader Ivan Lendl.
Federer, who is looking for a record sixth title here, will face either Novak Djokovic, Tomas Berdych or David Ferrer in the semifinals.
The other match on Thursday pits Rafael Nadal against Jo-Wilfried Tsonga.
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