Defending champion Stan Wawrinka wasted five match points before sealing a straight sets win over Japanese fifth seed Kei Nishikori to reach the semi-finals at the Australian Open on Wednesday.

The Swiss fourth seed won 6-3, 6-4, 7-6 (8/6) in just over two hours and will now face either top seed Novak Djokovic or eighth seed Milos Raonic for a place in Sunday’s final.

Wawrinka: beats Nishikori

Wawrinka dominated with his serve and backhand to reach his third Grand Slam semi-final and a chance of playing in back-to-back finals at the Australian Open.

He broke Nishikori’s service three times and lost serve only once, while winning 86 percent of his first-serve points.

“I am still nervous about that tiebreak, I was a bit defensive, it’s never easy, you have to go for it and I’m happy to get through,” Wawrinka said about blowing five match points.

“It’s going to be a tough one in the semi, but I’m playing well so I am happy to be back again to be playing in the semi-final. I will watch tonight’s match and then practice tomorrow.”

Wawrinka set out to attack Nishikori’s forehand and got a service break in the fourth game after Nishikori netted a forehand.

Nishikori: falls to Wawrinka

The Japanese superstar fought off two set points in the eighth game before Wawrinka served out for the opening set.

Nishikori again came under pressure in the second set, fighting off a break point in the third game before he was broken in the fifth by a scorching Wawrinka backhand winner.

The Japanese star saved three break points in his next service game before Wawrinka served out for a two sets to love lead.

The US Open finalist jumped out to a 2-0 lead in the third set, but the Swiss quickly broke to love with a cracking backhand cross-court winner and then levelled up.

Both players swapped breaks early in the third set before it went to a tiebreaker and Wawrinka stormed to five match points.

But he lost them all before Nishikori attempted a netted drop shot from the baseline to set up another match point.

Wawrinka made no mistake with an ace to clinch victory.