As Venus Williams entered Centre Court for her 24th Wimbledon appearance at age 43, greeted by a standing ovation, she held a green exercise band overhead with both hands and stretched it while striding to her sideline seat.

Once her first-round match against Elina Svitolina began, Williams played like a throwback version of herself. Those big serves. Those crisp strokes. Quickly, she was a point from a 3-0 lead on Monday.

And then, moving forward to attempt a volley, Williams slipped on the green grass. Her right foot gave way. She collapsed to the ground. She shrieked and clutched at her right knee, which already was covered by a beige sleeve. Williams twice was treated by a trainer — including getting that knee taped up during a medical timeout after the first set — and although the American kept playing, she could not manage to overcome 2019 Wimbledon semifinalist Svitolina in a 6-4, 6-3 defeat.

“I'm not sure what I've done. I'm going to have to investigate it tomorrow. It's late today. But it was quite painful,” Williams said. “Grass is inherently going to be slippery; you're going to fall at some point. It was just bad luck for me. I started the match perfectly. I was literally killing it. And then I got killed by the grass.”

Williams, a former No. 1 now ranked outside the Top 500 after a series of injuries that limited her to 22 matches since the start of 2021, was the oldest player in this year's field and the fourth-oldest to compete in the main draw at Wimbledon.

“Right now, I'm kind of in shock. I can't believe this happened. It's bizarre. I'm still processing it at the moment,” Williams said at her news conference, more than an hour after the match ended. “What makes this one hard to process is that I've had so many injuries. ... This is not what I want for myself.”

Svitolina was only 2 when Williams made her Wimbledon debut in 1997 and just 5 when Williams won the event for the first time in 2000.

“It's always a pleasure to play against Venus,” Svitolina said, calling her opponent a “big legend.”

No. 1-ranked Iga Swiatek, who won her opening match 6-1, 6-3 against Zhu Lin, used that same term — “legend” — to describe Williams.

“I admire (how) she still finds motivation to play. I think it's amazing. She really must love the game, like truly,” said Swiatek, who has won four major titles but is yet to get past the fourth round at the All England Club.

Something of a surprise arrived at No. 1 Court just before darkness arrived Monday, when Coco Gauff — who burst onto the scene at age 15 by beating Williams in the opening round at Wimbledon — was eliminated by Sofia Kenin 6-4, 4-6, 6-2 in a highlight-reel matchup between two Americans.

While Kenin did win the 2020 Australian Open, even knocking off Gauff along the way, she had exited in the first round at each of her past three majors, is ranked just 128th and needed to go through qualifying rounds to get into the main draw at Wimbledon. Gauff, meanwhile, was seeded No. 7 and established herself as a consistent Week 2 presence at Slams, including a run to the French Open final last year.

Williams' other four titles at the All England Club arrived in 2001, 2005, 2007 and 2008, too, along with a pair of U.S. Open trophies in singles — plus 14 in women's doubles with her younger sister, Serena, who retired after last season.

The older Williams also was the runner-up at Wimbledon four times, most recently during a resurgent 2017, a season in which she reached a total of two finals and another semifinal at majors. Since then? Williams — who announced her diagnosis with Sjögren's syndrome, an energy-sapping auto-immune disease that can cause joint pain, in 2011 — has lost in the first round at 10 of her most recent 15 Grand Slam events.

There were some vintage moments on Monday. Serves at up to 117 mph. The big cuts on forehands and two-handed backhands that either produced clean winners or led to forced errors by Svitolina.

There also were 33 unforced errors, 18 more than Svitolina. Williams' total in that category included eight double-faults.

The tumble that brought a hush over the stadium came after merely 12 minutes of play and, as she stayed down on the grass, getting chalk on her left leg, it appeared as if she might need to stop. The chair umpire rushed over to check on Williams. So did Svitolina, carrying a white towel to tuck under Williams' head.

“I'm a competitor. That's what I do for a living. I did what I could today,” Williams said later. “I've played through a lot of matches and won a lot of matches injured. Its kind of a specialty of mine. I just never figured it out today.”

Still, the crowd certainly was appreciative of the persistence and effort Williams displayed on Monday, rising to salute her and shower her with applause when she left the court with a quick wave and a slight hitch in her step.

During the match, there were too many cries of “Go, Venus!” or “You can do it!” to count. Truth is, both players are sympathetic figures, and Svitolina, who is 28, heard her own support from the stands. She is from Ukraine — which has been under attack from Russia for nearly 1 1/2 years — and returned to the tour in April after giving birth in October to the first child for her and her husband, tennis player Gael Monfils.

Svitolina wound up with more aces than Williams, 6-2, and nearly twice as many total winners, 28-16.

“Grass takes a lot out of the legs and you have to bend your legs to get to all these shots,” said Svitolina, who used to be ranked as high as No. 3 but is now No. 76 after the time off and, like Williams, received a wild-card invitation from the All England Club. “Venus plays really quick and I had to really work hard for today's win.”