Novak Djokovic reached an eighth Australian Open final as he beat Roger Federer in straight sets. The world number two maintained his impressive record against Federer with a 7-6(1) 6-4 6-3 victory, stretching his flawless head-to-head at Grand Slams against the Swiss into an eighth year. Djokovic, who has won all seven of his previous finals in Melbourne, will face either Alexander Zverev or Dominic Thiem in Sunday's final. The preamble was dominated by Federer's fitness after the Swiss maestro nursed a groin injury through his five-set quarter-final win over Tennys Sandgren on Tuesday. But that initially acted as a brilliant disguise as Federer ripped through his opponent's serve at the first opportunity, breaking with a trademark backhand down the line. Federer looked certain to take the opening set, leading 4-1 and 0-40 on the Djokovic serve, when his physical limitations started to show. Djokovic held serve, broke back to love and raced through the resulting tiebreak 7-1. Federer immediately called a medical timeout and from that point on, the result looked inevitable. "It could have definitely gone a different way if he used those break points," Djokovic admitted afterwards. "He started off really well, I was pretty nervous at the beginning. I want to say respect to Roger for coming out tonight. He was obviously hurt and wasn't at his best, even close to his best, in terms of movement." If this was to be Federer's final outing in Melbourne, he was not going to disappear without a fight. There were plenty of glimpses of his brighter self as the occasional winner swooshed off his racket but Djokovic always looked to have the match under control. A solitary break at 5-4 was enough for Djokovic to pinch the second set, with the Serb unleashing a roar in a subdued Rod Laver Arena that was willing a fairytale comeback. Federer continued to scrap, even as the result looked a formality, and forced Djokovic to serve it out after battling from 0-30 in his final service game. But that was where his resistance ended. Djokovic secured victory when Federer netted, sending his quest for a record eighth title into a final chapter. Djokovic will seek a 17th Grand Slam title against Zverev or Thiem, both of whom are yet to taste success at a major. Federer, on 20 titles, remains his long-term target.