India's Yuki Bhambri and his Dutch partner Robin Haase squandered three match points in the deciding set to go down in the Australian Open men's doubles first round

India's Yuki Bhambri and his Dutch partner Robin Haase on Friday entered the semifinals of the Brisbane International ATP Tour tournament

It is Roger Federer's first time back at the summit since October 2012 having first claimed the top position in February 2004.

Haase, 26, explained in the daily Volkskrant that, after undergoing the test, he received a letter from the ATP advising him "to get a lawyer" and indicating that he would have to undergo three more tests in the following two weeks.

The second-seeded German, won also won the event 12 years ago, maintained his slim chance of qualifying for next month's ATP finals in London.

Tipsarevic has had a dreadful run this season as he has slipped out of the top 10 in a downward trend which has accelerated over the last four months.

Djokovic dropped his serve to fall behind 2-1 in the opening set but broke back immediately and took control from there against his 32-year-old opponent.

The third seed, playing his first Grand Slam match since winning the US Open, won 6-3, 6-1, 6-3 in 1hr 37min on Rod Laver Arena.

The 20-year old 217-ranked Bhambri had his chances, especially in the first set when he held breakpoints against Haase who himself allowed the Indian to hold serve in the third game after leading 40-0.

Juan Martin del Potro defeated Slovenian qualifier Grega Zemlja 7-5, 6-3 on Sunday to win his first title at the Austrian Open and improve his standing in the race to the year-end championships.