Serena Williams defeated Japan's Naomi Osaka in a rematch of their U.S. Open final on Friday to advance to the Rogers Cup semifinals. The 37-year-old American beat her 21-year old opponent 6-3, 6-4. 

Last September, Williams lost to Osaka in controversial 6-2, 6-4 match. This was Williams' first event back since losing the Wimbledon final last month and the first time she has faced Osaka since the US Open. 

The 23-time Grand Slam champion said the familiarity with Osaka's game helped her secure the victory at the Rogers Cup.

"I knew her game a little bit more, so that's a little easier. I'm just overall a little bit better," Williams, ranked 10th and seeded eighth, said. "I know her game. I watch her a lot. I know what I need to do to hopefully try to get a win today, and it helped a little bit. I go into every match thinking I can do it, but sometimes that doesn't happen."

She joked that her goal was to just win a set this time, because Osaka has beaten her twice.

Osaka, who calls Williams her "tennis mom," is not hung up on the loss, and admits Williams put up an incredible fight.

"I'm not really mad at this," Osaka said. "I don't think it was up and down. I think I played pretty well. And she just played amazing, which, that's what she does... I just feel like the entire match I was a bit too defensive. I know that can't be helped when I'm playing against her."

With the win, Williams will go on to face Czech qualifier Marie Bouzkova on Saturday. Bouzkova was leading fourth-seeded Simona Halep when the Wimledon champion suffered from a left Achillies problem and was forced to end the match.  

Williams is no stranger to the Rogers Cup. She has won it three times: in 2001, 2011 and 2013 and has a tournament record of 33 victories in 37 matches.