(REUTERS) – Serena Williams shook off some COVID-19 layoff rust to grind out a 7-6(6) 3-6 7-6(0) win over Dutch qualifier Arantxa Rus on Monday to move into the third round of the Western and Southern Open.

Williams’ matches are a magnet for fans but with no spectators allowed onto the Billie Jean King National Tennis Center grounds due to COVID-19 safety protocols, the atmosphere inside a steamy Grandstand was one of relief rather than excitement as the 38-year-old American trudged off following the hard-fought victory.

“I was fine,” said Williams, when asked about playing without fans in the stands. “At one point I was pumping my fist and saying, “Come on”.

“I had a crowd in my head or something.

“It was actually funny to me. For me, it was like there was a crowd there.”

By the time Williams arrived on court to face her 72nd ranked opponent, she was the highest seed left in the women’s draw after number one Karolina Pliskova and number two Sofia Kenin lost their opening matches on Sunday.

And Williams needed to draw on all her experience and survival instincts to ensure she did not join them at the exit as Rus put the former world number one through a near three-hour workout.

All four matches Williams has played since the WTA Tour restarted following the COVID-19 hiatus have gone to three-sets.

Monday marked the first exhausting day in what could be a three-week tennis marathon for Williams, who will be hoping her long search to win an elusive 24th grand slam title — and equal Margaret Court’s record tally — will end on Sept. 12 with victory in the U.S. Open final.

Down 6-5 in the third set and with Rus serving for the match, a drained Williams looked down for the count but she picked herself up to break the Dutchwoman to force a deciding tiebreak. She then moved in for the kill to win it 7-0.

After working her way into the main draw through qualifying, Rus came in match sharp while Williams looked sluggish on a hot and humid New York afternoon. She spent much of the first set trying to tame a misfiring forehand.

While Williams fitness has been questioned, her fighting spirit has never been in doubt and never more than in the third set.

Despite showing signs of fatigue, Williams insisted she was fit and ready for the task ahead.

“I’m actually super fit and I’m super ready,” assured Williams. I feel like I’m ready for anything.”