Novak Djokovic recovered from a set down to progress to round three at Indian Wells ©Getty Images

World number one Novak Djokovic of Serbia survived a scare as he fought back from a set down to beat American Bjorn Fratangelo to reach the third round of the BNP Paribas Open at Indian Wells.

Djokovic, winner of 11 Grand Slam titles, was lethargic early on and Fratangelo, boy’s singles champion at the 2011 French Open, capitalised to take the first set 6-2.

But the Serbian found his form with devastating effect as he levelled proceedings by racing to the second set 6-1.

The momentum was then with Djokovic, who won the Australian Open back in January, as he closed out victory by winning the third 6-2.

"All in all, it was just not a great performance," the Serbian said.

"But, you have to deal with it, accept it.

"A win is a win and hopefully the next one will be better."

Spaniard Rafael Nadal is also through after he overcame Gilles Muller of Luxembourg 6-2, 2-6, 6-4.

The build-up to the competition at Indian Wells for the fourth seed was dominated by fresh doping claims after Russian’s five-time Grand Slam champion Maria Sharapova announced she had failed a drugs test for meldonium, which was added to the World Anti-Doping Agency prohibited list on January 1, at the Australian Open.

Nadal has constantly faced allegations of taking banned substances during his career, the latest of which came from ex-French Minister for Health and Sport Roselyne Bachelot.

She claimed that the reason Nadal had missed seven months back in 2012 was because he had failed a drugs test.

Women's top seed Serena Williams is through to round four after she beat Yulia Putintseva of Kazakhstan
Women's top seed Serena Williams is through to round four after she beat Yulia Putintseva of Kazakhstan ©Getty Images

These suggestions were refuted by the Spanish Olympic Committee and came after the 14-time Grand Slam champion had again insisted he was clean.

Fifth seed Kei Nishikori of Japan is also through to round three after he ousted Kazakhstan’s Mikhail Kukushkin in straight sets 6-3, 6-3.

In the women’s draw, top seed Serena Williams was made to work hard for her place in the next round as she clinched a hard-fought 7-6, 6-2 success over Yulia Putintseva of Kazakhstan.

The formidable American needed 50 minutes to claim the opening set before dominating the second to seal victory and keep her quest for the Indian Wells crown alive.

Third seed Agnieszka Radwanska of Poland breezed to a commanding 6-2, 6-1 win in her match with Romania’s Monica Niculescu, while eighth-seeded Czech player Petra Kvitová needed three sets to get past Sweden's Johanna Larsson 6-3, 4-6, 7-5.