Barry's best bets
Sky Sports pundit Barry Cowan will join us each day of the ATP World Tour Finals to provide his views on the day's action.
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The season-ending tournament, taking place at London's O2 Arena, features the world's top players of 2012, including Andy Murray, Roger Federer and Novak Djokovic.
The former British star, part of the Sky Sports team at the event, will have a charity bet with Sky Bet each day - all money won will be donated to Cancer Research.
Barry's charity bet for Sunday's semi-finals is:
Barry says: "Andy Murray and Novak Djokovic have been the two standout players this week and I fully expect them to meet again in the final.
"I don't think either one will be troubled too much in the semi-finals and back them both to win in straight sets."