Azarenka battles into decider

Victoria Azarenka's quest for back-to-back Australian Open titles remains on track after the world number one accounted for a plucky Sloane Stephens in their semi-final clash at Melbourne Park on Thursday.

The Belarusian defeated the American teenage sensation 6-1 6-4 in one hour and 41 minutes but was made to fight for the victory as she needed no less than six match points to finally seal the result and book her place in the decider against China's Li Na who earlier defeated Maria Sharapova in the other women's semi-final.

After easily winning the first set in 33 minutes, Azarenka was pushed much harder by Stephens, who sensationally defeated 15-time grand slam champion Serena Williams on Wednesday, in the second set as temperatures hovered in the mid-30s on Rod Laver Arena.

The number one seed wasted five match points in a marathon ninth game, which went longer than 12 minutes, and Stephens made her pay by making good on her third break-point opportunity to trail 5-4.

The number 29 seed, playing in her maiden grand slam semi-final, appeared to have all the momentum especially considering Azarenka immediately required two consecutive medical timeouts.

But the world number one proved why she holds her ranking by breaking Stephens for the seventh time in the match in the next game to progress to her third grand slam final in five attempts and end the American's fairytale run at Melbourne Park.

Despite recording more double-faults (6-2), Azarenka - who appeared to pick up a left leg injury of some kind - hit more winners (21-14), committed fewer unforced errors (31-42) and had a far better percentage of first-serve points won (64-45).

Azarenka began the match in ruthless fashion by breaking Stephens first up and then serving a love game to quickly lead 2-0.

Stephens responded to win the next game but she was always fighting much harder to hold serve than Azarenka and two games later the Belarusian earned a double break when, after three deuces and two game points to the American, she converted the second of her break-point chances of the game.

Azarenka shot out to a 40-15 lead in the next game and a wild forehand from Stephens gave the reigning Australian Open champion another easy hold of serve to lead 5-1.

Azarenka quickly brought up three set points in the next game, and only wasted one, with a clever lob over Stephens at the net falling just inside the baseline, ensuring the number one seed wrapped up the first set.

Azarenka's dominant serving performance continued unabated in the second set as she went up 1-0 and in the next game capitalised yet again on Stephens' inability to hold serve by saving another game point and breaking once more.

Stephens began showing some fight by winning the next two games but Azarenka got her break advantage back by chalking up a love game on Stephens' serve in the sixth game to lead 6-1 4-2.

In the next game, Azarenka had advantage and the chance to go up 5-2 but served consecutive double faults to hand Stephens a break point which the American converted to trail 4-3.

The Belarusian regained her composure to break Stephens for the sixth time in the match to go up 5-3 and, although she failed to ice the result in the next game as the American won her third break point of the match after saving five match points, won the last three points of the contest to claim the win.