Andy Murray was left angered by a change of balls during his three-set defeat to Tomas Berdych at the Paris Masters.
Berdych called for an unscheduled switch of balls in the deciding set of their quarter-final clash, something which Murray believes had an effect on the match.
"Tomas decided that the balls were too soft - which they weren't," Murray said.
"The umpire gave him three brand new balls to serve with. I wasn't aware that they were just changing three brand new balls.
"Then that totally changed the way the ball plays and the court plays."
Berdych will now take on Roger Federer for a place in the final after the Swiss beat Juan Monaco in straight sets.
