Andy Murray beats Tomas Berdych in a third -set tie-break in Group A opener . Serbian saves a match point to triumph at the season-ending championships . first seed Tomas Berdych upsets home hope Andy Murray in Monday 's third game . World No . 1 World No . 4 Murray struggling with groin injury and may quit the tournament .
Andy Murray beats Tomas Berdych in a third -set tie-break in Group A opener . Serbian saves a match point to triumph at the season-ending championships . first seed Tomas Berdych upsets home hope Andy Murray in Monday 's third game . World No . 4 Murray struggling with groin injury and may quit the tournament .