Serena and Venus Williams didn't expect to still be playing on tour at this time, but say their own competitiveness and impact on others has kept them going.
"I definitely didn't see myself playing tennis at my age. I just thought I would have been gone doing other things," said Serena, 32, at Montreal. "But it just so happens that I love to play, I love to compete. I'm having fun. I enjoy it."
"I didn't think that I'd be playing this long, no. But I thought I'd be running my own business by now," agreed Venus, 34, who has just returned to the Top 20.
In addition to her seven Grand Slam titles, Venus is also known for her efforts to secure prize money equality at Wimbledon, and described her reputation as one of the most important things she has achieved.
"Well, I think what I'm most proud of is that so far I've come this far without falling on my face," she said. "I want to try to keep that up. So once I'm done I can look back and say, I didn't make a fool of myself."
The elder Williams has also stood out for her return to professional tennis following a diagnosis of Sjogren's syndrome, an auto-immune condition that causes fatigue.
"I play because I love it and I want to win titles, but I also play for that. I don't want to lay down," she said. For me, I think I'm playing for my own redemption."
Having been on tour for 15-20 years, the sisters have also seen others inspired by them, both on and off the court.
"We've had such a great impact. I think having been, you know, pretty much one of the first African-Americans to do well, then to see all the African-Americans, even some Canadians here playing really well, it makes me feel really good," said Serena.
"I think in a lot of ways the work that we've put in on the court has been able to give so much to so many different people in so many different ways. That was a result that we, as sisters or as a family, never saw coming," said Venus.
The two played each other in the semifinals of Montreal, with Venus winning in three sets.