Coco Gauff has expressed her desire to face Jessica Pegula again this week after defeating her friend and rival at the WTA Finals.

The former doubles partners faced each other in their opening match in the group stage of the season-ending championship and Gauff prevailed 6:3 and 6:2 in 75 minutes.

Afterwards, the world No. 3 admitted that it was difficult to face Pegula even though they no longer played doubles together.

Gauff got her WTA Finals campaign off to a successful start on Sunday, moving to the top of her group with an easy win in straight sets. The 20-year-old scored 16 winners and defeated Pegula, a player she often struggled against.

The world No. 3 came into the game with a 1-4 record against Pegula, with the 30-year-old outshining her in the WTA Finals semi-final 12 months ago. But Gauff flipped the script and managed five breaks to secure the victory.

Afterwards, the former US Open champion admitted it was difficult to play against such a good friend and said she also wanted Pegula to reach the group stage so they could see each other again.

When asked what she was most proud of, Gauff told Sky Sports: “Just staying solid. It's a lot of height. I’m not used to this at all.”

“I'm just trying to stay solid and it's obviously difficult for me to play against them, but I'm glad I got through today. I’m cheering for them, so I hope we play again in the final.”

The 20-year-old often struggled with Pegula and shared what she learned from their previous meetings. “I just stick with it, every time, at every point,” explained Gauff.

“She doesn’t really give you anything. I feel like I have to earn every point. I think that’s exactly what I learned the most.”

Gauff and Pegula have something in common: both changed their coach this season. Pegula parted ways with David Witt after the Australian Open and hired Mark Knowles, while Gauff and Brad Gilbert parted ways after the US Open. The world number 3 has now signed Matt Daly.

Gauff has already started tinkering with elements of her game since working with Daly, particularly trying to improve her serve after committing 19 double faults during her US Open loss in the summer. It didn't always pay off, but she had much better stats against Pegula, hitting two aces and two double faults.

When asked if she preferred to wait until the off-season to make changes, the eight-time title winner replied: “I definitely implement things little by little and it goes up and down.”

“I mean, everyone saw my game in China, it was a tough service game and I was able to improve. I’m just trying to get through the rest of this season and try to serve well and today was a great day for me.”

Gauff will now face Iga Swiatek in their next group stage game on Tuesday, while Pegula faces Barbora Krejcikova.