Novak Djokovic struggles at first, but beats Grigor Dimitrov at BNP Paribas Open

For a while Tuesday, the No. 1 men’s tennis player in the world, Novak Djokovic, didn’t play up to his rating and the No. 31 player, Grigor Dimitrov of Bulgaria, played well above his.

But, as so often happens in big tournaments such as the BNP Paribas Open at Indian Wells, form returns. Djokovic’s did late in the first set, after trailing, 4-1 and 5-2. That was helped by several key double faults by Dimitrov, which became gift wrapping in a 7-6 (4), 6-1 victory by Djokovic.

That marked 15 consecutive victories to start the year for the Serbian star, who won his third straight Australian Open in January and has won six Grand Slam event titles, including five in the last nine majors. Djokovic’s most recent loss was Oct. 31, to rising U.S. star Sam Querrey, whom he will play next in the quarterfinals.

Querrey advanced after a long struggle with unseeded Marinko Matosevic of Australia, 7-6 (5), 6-7 (7), 7-5.

“I just stuck around, stuck around, and closed it out with some good serves,” Querrey said.

Los Angeles’ Mardy Fish, a former top-10 player, who was expecting to have a bumpy road in a comeback from some heart problems, made it through an opening-round victory and gave No. 8 Jo-Wilfried Tsonga all he could handle in a 7-6 (4), 7-6 (0) third-round loss on Stadium 1.

“It hasn’t taken too long to get the form back,” said a surprised-sounding Fish, who hadn’t played in an ATP event since the fourth round of the U.S. Open last year.

Also advancing on a day of predictability were the women’s finalists here last year.

Maria Sharapova, an Australian Open finalist this year, took awhile to figure out Lara Arruabarrena-Vecino of Spain and then dispensed of her, 7-5, 6-0. Victoria Azarenka, No. 2 in the world behind Serena Williams and last year’s Indian Wells champion, got past Urszula Radwanska of Poland, 6-3, 6-1.

Sixth-seeded Sara Errani of Italy also advanced, beating No. 9 Marion Bartoli of France, the 2011 Indian Wells runner-up, 6-3, 6-2.

bill.dwyre@latimes.com