Belinda Bencic hands Serena Williams final Toronto defeat in rematch of 2015 thriller

WATCH: Serena soared in her opening round against Parrizas-Diaz but faced stiffer opposition against Bencic on Wednesday.

Belinda Bencic ended what looks to be one of the final tournaments of Serena Williams’ peerless career on Wednesday, handing the 23-time Grand Slam champion a 6-2, 6-4 defeat at the National Bank Open in Toronto.

"I wish I could have played better today but Belinda played so well," Williams said through tears on court. "It's been an interesting 24 hours, that's for sure."

"It's been a joy playing in front of you guys all these years," she added before clarifying the "goodbye" was to Toronto—and she still had a few more tournaments left to play.

It was on this court in 2015 when Bencic scored the biggest win of her career over Serena, who was, at the time, in search of a Calendar Year Grand Slam. Then just 18 years old, Bencic rode that momentum to her first WTA 1000 title in Canada to foreshadow her ascent into the Top 10.

Facing off in an official match for only the second time since then, the No. 12 seed and reigning Olympic champion maintained her ascendency in the wake of Williams’ announcement of an imminent retirement and edged through their highly-anticipated clash in under one hour and 17 minutes on Center Court.

While Bencic has played a solid schedule of tournaments throughout 2022, Serena was playing only her third singles match of the season, having made an unexpected return to action at Wimbledon, where she fell in three dramatic sets to Harmony Tan. After playing practice partner to elder sister Venus at the Citi Open, the former world No. 1 made her second tournament appearance in Canada—a tournament she played for the first time 22 years ago—where she won a hard-fought opening round against Nuria Parrizas-Diaz and heavily implied her career was in its final phase.

“I can't do this forever,” she said after joking about seeing light at the end of the proverbial tunnel.

“So, it's just like sometimes you just want to try your best to enjoy the moments and do the best that you can.”

Her Vogue feature was released the following day, delving further into the idea that she would soon “evolve” away from tennis—triggering reaction from players, fans, and celebrities alike and making for an emotional encounter with Bencic now that word had become official.

If Bencic was feeling the weight of the occasion, she showed little signs in the early goings as she eased through several long games to twice break Williams in the opening set and survive a harrowing final game to earn the early advantage—striking 14 winners to just six unforced errors to start.

The understandably pro-Williams crowd attempted to lift their three-time champion early in the second set as she put together a trio of strong service holds, but Bencic responded each time and was first to break point with a strong forehand into the open court. Though the Swiss missed an easy backhand into the net, Williams couldn’t capitalize and threw in an ill-timed double fault to put the former world No. 4 in striking distance of victory.

Serving to stay in the match, Serena put down a vintage hold on the brink of defeat but Bencic was again unmoved, converting the first of two match points with a service winner to clear the finish line and win her 30th match of the season in under 80 minutes.

Bencic pulled Williams in for a hug at the net and immediately ceded the floor to the vaunted champion in her post-match interview.

"Tonight is about her," she said as cheers erupted from the crowd.

In a heartwarming farewell ceremony, Williams was handed flowers and a series of Toronto sports jerseys—both for herself and daughter Olympia, who was in the stands watching mom play this week.