Iga Swiatek underlined her status as the world's top player with an efficient 6-4 6-3 victory over Croatian Petra Martic at Wimbledon on Thursday, her 21st match win in a row.

The 23-year-old Pole triumphed at the Madrid and Rome Opens as well as taking the Roland Garros title, before switching to the Wimbledon grass and reaching the third round.Swiatek, who has won five Grand Slams but has never progressed beyond the quarter-finals here, looked comfortable on the Centre Court grass, though she was tested at times by Martic's hefty serve and groundstrokes.

"I'm happy to play in a solid way," Swiatek said. "I felt like I had control in most of the games when Petra served, but I couldn't really break it. I'm happy that I broke twice. That was a necessary thing to do to win these sets."

Martic, 10 years Swiatek's senior and ranked 85th in the world, fell and needed treatment after the seventh game of the first set but resumed apparently unimpeded.

Swiatek clinched the first set on her first break point with an attacking forehand that Martic could only dump into the net.

She broke Martic's serve in the eighth game of the second set, earned match point with a big forehand winner and finished the contest with a serve that Martic netted.

Swiatek meets 35th-ranked Yulia Putintseva of Kazakhstan in the next round.

"I'm kind of doing everything step by step and every match matters for me," Swiatek said.

"It's not like I'm going in the first rounds of Grand Slams knowing that I should win or I should take it for granted. I'm ready to battle even in the first rounds."