Just a bad day at the office, says Novak Djokovic after he is dumped out of the Australian Open

A deflated Novak Djokovic blamed a bad day at the office for his stunning second-round elimination at the Australian Open ­on Thursday by Uzbek wild-card Denis Istomin which condemned the Serb to his earliest grand slam exit in nearly a decade.

A strangely off-colour Djoko­vic bowed out 7-6 (10-8), 5-7, 2-6, 7-6 (7-5), 6-4 at Rod Laver Arena, the court where he won his sixth title last year and was widely tipped to clinch a record seventh in 10 days’ time.

In the women’s draw, Serena Williams dispatched Lucie Safarova 6-3, 6-4 but third seed ­Agnieszka Radwanska was a ­major casualty when she lost 6-3, 6-2 to Croatian veteran Mirjana Lucic-Baroni.

As the match slipped beyond his control, Djokovic, the second seed, could conjure little emotion to rally in the fifth set but he ­denied his competitive fires were lacking in the stunning upset.

“There was intensity, of course,” he said. “We played four and-a-half hours. It’s just that, you know, it’s one of these days when you don’t feel that great on the court, don’t have much rhythm, and the player you’re playing against is feeling the ball very well.

“I started the season very well. Again, it’s a tennis match. On a given day, you can lose. I mean, nothing is impossible.