Williams sisters stroll into third round

Serena Williams strolled to a 6-2 6-2 victory over Columbia’s Catalina Castano in the second round of the US Open in her bid to capture a second Grand Slam this year.

But the 23-year-old American admitted she was struggling in the testing conditions at Flushing Meadows.

“I’m definitely not at my best,” the eighth seed said. “Honestly, I’m under 50% (healthy). But I’ve won stuff under 50% before.

“I still made a lot more errors than I wanted to, a lot more than I’ve made in practise. I’m definitely moving a lot better than I have in the last couple of weeks.”

Her elder sister Venus, seeded 10th, also advanced with a 6-1 6-3 triumph over Maria Kirilenko, who had just four winners and committed 17 unforced errors.

Kirilenko gave Serena quite a fight last year at the French Open, taking a 4-2 lead in the final set before losing.

After getting crushed in the first set in this one, she rallied from a break down to tie Venus at three games apiece in the second set before dropping the final three games.

Venus awaits 20th seed Daniela Hantuchova in the third round after the Slovakian crushed Maria Emilia Salerni of Argentina 6-1 6-0.