TORONTO -- No.12 Belinda Bencic defeated three-time champion Serena Williams 6-2, 6-4 at the National Bank Open to advance to the Round of 16. Bencic will face Garbiñe Muguruza next.

Playing her first match since her essay in Vogue detailing the decision behind her impending retirement, Williams was greeted by a rapturous ovation from the Toronto crowd as she took to the court. Williams was bidding to win her first back-to-back singles matches since 2021 Roland Garros. On Monday, she defeated Nuria Parrizas Diaz in straight sets.

But in a rematch of their memorable semifinal duel on this very court in 2015, Bencic was able to control the match from start to finish with her serve. The 25-year-old from Switzerland faced just one break point in the match, which she saved.

How the match was won: Bencic also kept the return pressure on Williams from the first game. The Swiss won the toss, elected to receive and proceeded to earn two break points in the opening game. Williams saved them with clutch serving, but Bencic would go on to break Williams twice in the opening set, sealing it after 41 minutes.

The second set stayed level as Williams' found better success behind her serve, but Bencic finally got the break in the 3-3 game when Williams struck a double fault on break point. Bencic closed out the win after 1 hour and 17 minutes. Bencic finished with 25 winners to 13 unforced errors, while Williams hit 13 winners to 18 unforced errors.

Serena: "I'm ready for what's next"

Emotional post-match scenes: After the match, Williams stayed on court and fought off tears as she bid farewell to the Toronto crowd.

"It was a lot of emotions obviously," Williams told the crowd. "I love playing here, I've always loved playing here. I wish I could have played better but Belinda played so well today. It's been an interesting 24 hours." 

"As I said in the article, I'm terrible at goodbyes. But, goodbye Toronto."

Watch this: Serena Williams says goodbye to Toronto

Bencic on the win: "Of course it's super nice, but today it's a little bit more sad in a way. I don't really want her to retire. I feel like I've always, in a way you know what she's achieved and everything, all her legacy and career and everything. But now that it's soon to be over I feel like people, and me included, are realizing it even more.

"Just standing on the court against her today was just, yeah, really overwhelming, I would say."

It's going to be a tough task facing Williams over the next few weeks: "In a way with her it feels almost like I'm star struck every time I see her," Bencic said. "So it's difficult to play her. It's difficult to kind of put that aside and just like focus on the match. Because I feel like I just don't know how I then play because I feel like I'm paralyzed a little bit just like watching her.

"The crowd was incredible tonight. Just being part of that whole thing, it's just really very special for me as well and for her. And I think US Open it's going to be even more special. So good luck to everyone who has to play her."