The question now for Serena Williams at U.S. Open: How far can she go?

NEW YORK – The black skirt Serena Williams chose to wear for the close of her career was designed to have six layers, one for each of her U.S. Open titles. But that much of even the most gossamer fabric can feel heavy in the heat of battle, so ahead of the tournament Williams scrapped four of the layers and went on her way.

Wednesday night at Arthur Ashe Stadium felt a bit like Williams’ altered skirt.

All the accoutrements were still there, from Queen Latifah thanking Williams in a pretaped introductory video to the celebrities sprinkled throughout the crowd (Tiger Woods, the actress Zendaya), but her second-round match against Anett Kontaveit felt more workmanlike. Williams’ daughter Olympia was not in the stands for this match to watch and blow kisses at the crowd. This time, Williams eschewed the cape.

The result was a 7-6 (7-4), 2-6, 6-2 victory after a 2-hour, 27-minute grinding match that proved Williams’ physical abilities remain intact at age 40. It also showed that she remembers how to access a deep reservoir of fight.

Kontaveit, an Estonian ranked No. 2 in the world, challenged Williams to earn the win with brave returning and lightning pace. Her precise shots tested Williams’ patience, including one in the third set that just dusted the line so slightly that the record crowd of nearly 30,000 began to boo.

Williams wagged a finger to silence her supporters – no one was getting worked up by close calls here.

After entering the tournament with just four matches in the past 14 months and insecurity in her game, the question is no longer whether Williams’ body can perform up to Grand Slam tournament tennis. She blasted 11 aces to six pesky double faults, looking lithe and strong in her movement Wednesday.

“Are you surprising yourself with your level at the moment?” she was asked on court after the match.

“What?” Williams responded, in disbelief.

The question now is how far Williams can go.

She faces No. 46 Ajla Tomljanovic in the third round Friday, and before then will slip more practice under her belt by way of a doubles match with her sister Venus on Thursday evening. It is the first opening-round doubles match scheduled to open a night session on Arthur Ashe Stadium.

In the singles tournament, Williams said she feels in no hurry to leave now that she’s made herself comfortable.

“It’s no rush here,” she said. “There’s still a little left in me. We’ll see.”

Throngs of fans roaring their support will follow Williams for as long as she plays on. Record crowds have turned out for both of Williams’ matches this week, with 29,959 flocking to the tournament’s primary show court Wednesday.

The chair umpire’s first plead to the crowd to settle down came just 2 minutes after the match’s start.

They continued to bellow for the 23-time Grand Slam champion during points throughout the night, but the players settled into the atmosphere, relegating it mostly to the background, and carried on.

The nerves that tripped Williams into uncharacteristic double faults Monday seemed to have dissipated. Williams moved well at the start, pushing Kontaveit to hit one extra ball in rallies – even if Williams didn’t win them – and orchestrating points from start to finish.

Even then, rust was still evident early on. After securing her first break point in six tries to take a 5-4 lead, she handed Kontaveit the break back with a double fault.

But her serve came through when she needed it most: She clinched the first set tiebreaker with an ace.

Williams’ level dipped right away in the second set as Kontaveit zipped out to a 3-0 lead.

Williams finally won a game. But serving at 1-3, 40-0, Kontaveit pushed her to deuce, eventually sealing the game and squashing her opponent’s hope of a comeback with a sharp return that just clipped the sideline. Williams then sent a backhand into the net on the next point and, in a blink, Kontaveit held a 5-1 edge.

The Estonian closed the second set on an ace to even the match. Williams left the court to regroup and emerged refreshed, earning a 2-0 lead that bloomed into a 4-1 lead without Williams raising her level much at all – such was the advantage her experience and a supportive crowd provided.

But Williams did need her best to close. The biggest moment of the night came at set point with Williams serving to take a 5-2 lead. Kontaveit had her on the run but she dropped a lob, her second of the rally, on the baseline then closed in for a winner. AC/DC’s “Thunderstruck” rang out at Arthur Ashe Stadium.

Williams won the final game without giving up a point, feeling lighter, it seemed, with each passing moment.