Roundup: Djokovic in "strange semi-final" win over Wawrinka at Australian Open

Novak Djokovic triumphed over defending champion Stan Wawrinka in five sets for the third consecutive year on Friday to maintain his perfect semi-final record at the Australian Open.

In a topsy-turvy clash, the title holder and world No.1 both see-sawed in form before Djokovic dominated the final 30 mintues to prevail 7-6 (7-1), 3-6, 6-4, 4-6, 6-0 in three-and-a-half hours.

The seven-time Grand Slam champion will meet world No.6 Andy Murray in the Australian Open final for the third time, having defeated the Scot in 2011 and 2013.

Including his two wins against Murray, Djokovic has never lost a final at Melbourne Park, in stark contrast to the sixth seed who has been dumped in all three of his opportunities.

However, Djokovic need to play far more consistent tennis if he is to lift the Norman Brookes trophy for a fifth time after the bizarre performance with Wawrinka.

Following their 2013 fourth round that Djokovic won 12-10 in the fifth and the 2014 quarter-final that Wawrinka ended at 9-7 in the fifth, the 2015 edition had been built up as a A-grade match.

Instead, a B-grade Djokovic scraped past a fourth seed who rapidly fluctuating between his best and club-level tennis.

"It was just a strange match; a strange semi-final," said Wawrinka.

"In the end he won so I think he played enough to win the match."

Djokovic allowed his Swiss opponent a fifth set after the errant Serb hit not one winner in the fourth stanza.

Then, it was Wawrinka's turn to err when trademark backhand that had fired so seamlessly in the fourth became noticeably absent.

The fatigued Swiss' slowing footwork contributed to increasingly wayward shots - each of which took his chance of a title defence one step farther away.

"I'm proud of the fighting spirit that I had," said the victorious Serb.

"But the level of performance was not where I wanted it to be."

Through added psychological and physiological pressure, both players had trouble getting the first ball into play - Djokovic led with a paltry first serve percentage of 64.

Djokovic also lost serve easily, dropping five of 12 games when serving into the wind at the southern end.

The first hour was mostly devoid of the rallies characteristic of the pair's previous contests with both adjusting poorly to the conditions.

Despite Wawrinka administering eyedrops early in the match and often framing the ball, it was the reigning Wimbledon champion whose flurry of errors in the seventh game handed the half-blind Swiss the first break.

Try as he might to break up the baseline bashing pattern that their contest often fell into, the uncomfortable Serb's usually pure slicing was either beaten by the swift Swiss or overcooked in attempt to outfox him.

A break-back and tiebreak thrashing saw him again dominate until suddenly the patchy Wawrinka again found the form to force the decisive break in the second.

Only in the fifth set did someone finally truly move way ahead as the mentally-tired fourth seed found himself in a rut from which he never made it out.

He said he paid the price for a shortened off-season following Switzerland's historic David Cup victory.

"I was completely mentally dead and no battery," said Wawrinka.

"It was tough to focus on what I wanted to do."

Despite the bizarre swings in form throughout the match, the world No.1 maintained a positive outlook on his match.

"Getting to the finals in any way possible is a great achievement," he said.

Defending champion Wawrinka's exit from the tournament sees the Fab Four - Djokovic, Murray, Roger Federer and Rafael Nadal - now occupy the top four rankings for the first time since July 2013.

In the women's doubles final played earlier, China's Zheng Jie and Chinese Taipei's Chan Yung-Jan fought valiantly before going down to Bethanie Mattek-Sands and Lucie Safarova 6-4, 7-6 (7-5).

Chan has now lost three Grand Slam doubles finals after falling at the final hurdle in the Australian and U.S. Opens in 2007.

Mattek-Sands and Safarova now own a perfect record in Slams having paired up for the first time in Melbourne. Endi