Rafael Nadal repels Karen Khachanov to reach Australian Open fourth round

Rafael Nadal dropped his first set at this year's Australian Open, but still powered through to the fourth round with a 6-3, 6-2, 3-6, 6-1 defeat of Karen Khachanov.

The Spanish sixth seed — seeking to claim a record 21st major singles title in the absence of Roger Federer and Novak Djokovic — was in superb touch, as he took a two-set lead.

But Khachanov — seeded 28th in Melbourne — threw caution to the wind in the third set, stalling Nadal's charge with some ferocious hitting.

The Russian had lost all seven previous meetings with the 2009 Australian Open champion but briefly looked capable of mounting a comeback.

Nadal seized back control with a break of serve at the start of the fourth set, and, with the clock having ticked past midnight, finished off the match in a hurry. 

He remains on track for a potential quarter-final clash with world number three Alexander Zverev.

Earlier on day five, Zverev admitted he had been far from perfect but still eased into the fourth round without dropping a set after a 6-3, 6-4, 6-4 victory over Radu Albot on John Cain Arena.

The world number three struggled with his serve at times, but was always in full control against the 32-year-old Moldovan qualifier.

«Radu is [in] great form at the moment, he's obviously feeling the ball well, so happy to close it out in three sets,» Zverev said.

«Of course, I had much struggles on the court today, it didn't feel perfect. But who is perfect? At the end of the day I won and I'm happy with that.»

The German needed just a single break of serve in each set to set up a last-16 clash against what is likely to be more formidable opposition in the shape of Denis Shapovalov.

Albot was shaking his head at the quality of Zverev's play as early as the third game, but