MADRID (AP) ― Maria Sharapova rallied from a break down in the first set to beat Alexandra Dulgheru of Romania 7-5, 6-2 Monday and reach the second round of the Madrid Open.

The second-seeded Russian said she was still adjusting to changing weather conditions in Madrid and “the altitude as well” after winning the title in Stuttgart last weekend.

“It was a tough match,” Sharapova said. “I was really happy that I got that break back in the first set and was able to win in two sets.”

Victoria Azarenka of Belarus also advanced, outlasting Anastasia Pavlyuchenkova of Russia 7-6 (8), 7-6 (3).

Azarenka, who finished runner-up in Madrid the past two years, is returning from an ankle injury and said it was good to get a tough test right away.

“I don’t think I could have asked for a better match to start after a break,” she said.

The third-ranked Azarenka broke to go up 4-3 in the first set before Pavlyuchenkova broke back. Azarenka then saved three set points at 6-3 down in the tiebreaker.

“When you don’t play so much, you kind of lose that momentum,” she said. “In the tiebreak, I just tried to find my game to find the solution to make things happen for me.”

Laura Robson of Britain pulled off the first upset of the tournament, beating fourth-seeded Agnieszka Radwanska of Poland 6-3, 6-1 in a second-round match.

The 19-year-old Robson arrived in Spain coming off her sixth first-round loss of the year at the Portugal Open but was able to capitalize on her break points against last year’s Wimbledon finalist.

In the men’s event, 11th-seeded Nicolas Almagro of Spain advanced when Tobias Kamke of Germany retired injured after losing the first set 6-4.

Milos Raonic of Canada, American John Isner and Japan’s Kei Nishikori were also first-round winners.

The top-seeded players in the men’s draw, including Novak Djokovic, Rafael Nadal and Roger Federer, have a bye into the second round.