It is her 20^th appearance at the All England Club’s Wimbledon Tennis Championship and she has reached the semi-finals for the 10^th time. That is Venus Williams, as she braces up to win her sixth title. The last time she won the title was nine years ago. She advanced to the semi finals after beating Jelena Ostapenko 6-3, 7-5 on Tuesday under a closed roof on Centre Court.

Williams, who is 37 years old, made her Wimbledon debut in the same month that Ostapenko was born. “I love it. I try really hard,” Williams said of tennis. “There’s no other explanation. You do your best while you can. That’s what I’m doing.”

Williams will next face either second-seeded Simona Halep or Johanna Konta on Thursday. In the other women’s semifinal match, Garbine Muguruza will play either CoCo Vandeweghe or Magdalena Rybarikova. Muguruza beat Svetlana Kuznetsova 6-3, 6-4 on No. 1 Court.

Konta was next to play on Centre Court against Halep. On Court No. 1, Rybarikova was playing Vandeweghe.

On the men’s side, Novak Djokovic advanced to the quarterfinals by beating Adrian Mannarino 6-2, 7-6 (5), 6-4. That match, the first to be played under the roof on Centre Court at this year’s tournament, was postponed from Monday.

Williams went up a break early in both sets against Ostapenko, the French Open champion. But the 20-year-old Latvian broke back in the second set and pushed the score to 5-5. A few unforced errors later, though, and Williams broke again for a 6-5 lead before serving out the match.

Williams ended up with eight aces and only 13 winners. Ostapenko had one ace and 20 winners.

“Been working on that serve,” Williams said. “It’s working out for me just in time, just for these later rounds. I’d like to think that I can continue to rely on that as the matches continue.”

In the first match, Djokovic was up a break in the third set when he asked for a medical timeout and a trainer examined and stretched his right shoulder. The second-seeded Serb appeared to grimace in pain a couple of times as his shoulder was being checked.

“It’s been something that I’ve been dragging back and forth for a while now,” Djokovic said. “But I’m still managing to play, which is the most important thing.”

Djokovic was broken only once, in the second set. But the 12-time major champion, who won the Wimbledon title in 2011, ’14 and ’15, broke Mannarino early in the third and advanced to the quarterfinals at the All England Club for the ninth time.

Mannarino has never before reached the quarterfinals at any of the four Grand Slam tournaments. He also lost in the fourth round at Wimbledon in 2013. Last year, he lost to Djokovic in the second round at Wimbledon, also in straight sets.

Djokovic will face 2010 Wimbledon finalist Tomas Berdych, a man he has beaten 25 times in 27 matches, on Wednesday in the quarterfinals. One of those losses, however, was in the Wimbledon semifinals in 2010.

“He’s someone that understands the occasion of playing big matches, big tournaments,” Djokovic said. “He will not get overwhelmed by the stadium or whatever. He’s been there so many years. He’s got experience.”

The men traditionally have Tuesday off at Wimbledon, but Rafael Nadal’s five-set loss to Gilles Muller on Monday forced Djokovic’s match to be pushed back a day.

The rain then started at about 11:30 a.m. on Tuesday. The opening match on Centre Court was due to start at noon, so the roof was closed for the first time this year. The rain came and went into the afternoon, forcing the delay of the first women’s quarterfinal match on No. 1 Court.

There was a brief rain delay on the opening day of the tournament, but the roof stayed open and the rain went away.

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