TORONTO, Canada -- Surging teenager Bianca Andreescu became the first Canadian to win the Rogers Cup in 50 years, clinching the title after an ailing Serena Williams retired while trailing 3-1.

23-time Grand Slam champion Williams was suffering an upper back injury and the legendary American was unable to continue after falling behind an early break in the final. 

"It's not easy for Serena, for sure, to pull out, especially to pull out in a final," Andreescu said in her post-match press conference. "I know how she feels because I've done that many times in my short career. But sometimes you just have to listen to your body. And, yeah, it's not the way I wanted to win, but a win is a win. So I'm really, really happy."

Despite the unfortunate ending to the match, 19-year-old Andreescu emerged triumphant to hoist her second title of her season and career, after her sensational run to the BNP Paribas Open championship in March. 

"I would say that the win in Indian Wells was a hard-fought battle," said Andreescu. "So I felt like it was a sweeter victory at the time. But this tournament is at home. I've dedicated so much hard work and sweat on that tennis court and in this gym, so this tournament is definitely ten times more special."

Andreescu had not played an event since she gave a walkover to Kenin in the second round of Roland Garros in late May, but the rising star brought her best form during a week competing in front of her raucous home crowd, winning her first four matches in three sets before a long straight-set win over Sofia Kenin in the semifinals and the truncated victory over No.8 seed Williams.

The Canadian starlet picked up three Top 10 wins in the event, beating World No.5 Kiki Bertens and World No.3 Karolina Pliskova before World No.10 Williams’s retirement in the final, and now has a stunning 7-0 record against Top 10 players in her career. 

"Before the match, I was really, really nervous," Andreescu admitted. "I'm playing Serena in the finals of the Rogers Cup. So I was definitely nervous, but I think I handled the nerves really well. I mean, before situations or scenarios happen, I'm pretty anxious. But once things get going, then I'm totally cool."

Currently ranked World No.27, just off of her career-high of No.22, Andreescu will be rewarded for her success with a Top 20 debut in the WTA Rankings on Monday. She is projected to rise all the way to World No.14.

Williams survived break point to hold onto her serve in the first game of the match, but Andreescu slid to an early break for 2-1 after forcing errors from the American, including a double fault on the second break point of the game.

Andreescu used a series of fiery forehands to consolidate her break and move to 3-1, and after that game, Williams immediately moved to her chair. The American, clearly in pain, stopped the match, and Andreescu, who has suffered through weeks of inactivity this year due to injuries, quickly came over to Williams's chair to console and converse with the three-time Rogers Cup champion.

"I didn't notice anything whatsoever," Andreescu said, regarding the American's injury. "It was very surprising. But sometimes things happen, and, sadly, it had to be like that. But I wish her the fastest recovery."

"'You're going to bounce back,'" Andreescu said she told Williams during their post-match chat. "'You've dealt with so much in your career, this is just a minor setback for a major comeback, I'm sure.' And she was really nice. She was saying very nice things about me, so I really appreciated that."

In her own post-match press conference, Williams explained the injury problem. "It started yesterday in my match and it just got worse," said the American star. "Just my whole back just completely spasmed, and to a point where I couldn't sleep and I couldn't really move."

"I don't want to get this far and not at least try," said Williams. "I think I would have really regretted not at least going out there and seeing maybe if a miracle happened."

Williams said that she thought Andreescu is "a great girl, always have. That's why I have always wanted to play her. She's just a fabulous personality."