Former American Davis Cup captain Patrick McEnroe has blasted Victoria Azarenka's decision to take a controversial medical timeout in Thursday's Australian Open semi-final against Sloane Stephens.

Azarenka left the court for nine minutes shortly after letting five match points slip against the teenager.

The defending champion has insisted that she needed treatment on a back injury, but McEnroe believes that she took advantage of a rule which is against the spirit of the game.

The younger brother of John McEnroe told ESPN: "Let's cut to the chase here, what she did is within the rules and that to me is the biggest joke about this whole incident.

"What happened out there was an absolute travesty, I don't like what she did, I thought it was Bush League but that is besides the point.

"It is time for the tennis officials to get together and realise that this rule is being manipulated and enough is enough. They are taking advantage of the rules and it is horrendous for our sport."

Azarenka regained her composure to record a 6-1 6-4 victory over Stephens and advance to play Li Na in Saturday's final.