WIMBLEDON, England — Serena Williams again was pushed to three sets before winning, then complained a bit about having to play on Court 2 instead of Centre Court or Court 1.

By the looks of things so far, Williams is going to face a true test every time she takes the court this year at Wimbledon, which she has won four times.

“I definitely feel like I started slow,” said Williams, who wondered aloud afterward why she and her sister Venus each had to play on Court 2, while top men like Federer, Djokovic, Nadal and Andy Murray have been on one of the two principal courts for all of their matches this week.

“I got a little tight out there,” Williams added, “and I just need to relax.”

Tournament spokesman Johnny Perkins said there was no intentional snub, noting that several factors go into scheduling decisions, including TV broadcasting considerations, where players stand in the draw, and what ticket-buyers want to see.

Consider it a testament to her skill and grit that Williams is into the third round. This is only her second tournament in the last 11 months after two operations on her right foot, clots in her lungs, and surgery to remove a pool of blood that gathered under the skin of her stomach.

Her father, Richard, said he would have preferred if she would have waited another three months before coming back, just to be sure she was fully healed.