Threaded with emotion
Bencic fired eight aces and broke Serena twice in the first set and once in the second, advancing on her first match point. But as Bencic herself said in the post-match interview on court: "Tonight is about her."
And as expected Serena's farewell on-court interview was threaded with emotion.
"I love playing here, I've always loved playing here," she said, choking up as fans who cheered her throughout the match called out their appreciation. "I wish I could have played better tonight, but Belinda was playing so well."
Serena, who turns 41 next month, had beaten Spaniard Diaz for her first singles victory since the 2021 French Open, 14 months ago. But it sent shockwaves through the sport when she revealed in an essay in Vogue magazine and an Instagram post that "the countdown has begun" to her retirement from the sport.
Serena did not specify an actual retirement date but is expected to compete next week in Cincinnati before travelling to the US Open, which starts on August 29. She has lifted the US Open title six times, including her first Grand Slam triumph at the age of 17 in 1999.
"It's been a pretty interesting 24 hours," said Serena, who remains one shy of the all-time record of 24 Grand Slam singles titles won by Margaret Court. "Like I said in my article, I'm terrible at goodbyes," she said, her voice breaking. "But, goodbye," she said, then adding with a laugh "Toronto." "It's been a joy playing here all of those years."
Serena's match was preceded by a video tribute played for fans. Before she left the court she was presented with jerseys from the NBA's Toronto Raptors and NHL's Toronto Maple Leafs - and with a child's version of the same for daughter Olympia.
In explaining that she was "evolving away" from tennis in the Vogue article, Serena said she wanted to focus on family life and new business ventures.