PARIS, France - Russian teenager Anastasia Potapova announced her arrival to the game's biggest (and newest) stage on Sunday, and from her first practice, the revamped Court Philippe-Chatrier's maiden victor was ready to take Roland Garros by storm.

GALLERY: Pictured in Paris - Potapova shocks Kerber

"I felt very comfortable, like I was playing at home," she dreamily recalled in a phone interview following her emphatic upset of former World No.1 Angelique Kerber. "I felt every angle, every line."

That comfort turned to confidence as she closed out the reigning Wimbledon winner, admitting she felt no nerves as she blasted that final backhand return and forced the German's forehand reply to float wide.

"I knew what I wanted, and I was just going for it. This is what I'm living for. For now, I feel much more confidence in my game and my movements, but that was today. Tomorrow is going to be another day, so I’ll have to start over again, and go for it."

The 18-year-old, who scored her first Top 20 win over Anastasija Sevastova at the J&T Banka Prague Open in April, has never been one to live in a result for too long. She expressed a similar sentiment shortly after winning the Wimbledon girl's singles title in 2016.

Her tenacity and fighting spirit have also been hallmarks of her career, helping her qualify for her first Grand Slam main draw at the All England Club the following year, and reach two finals at the Moscow River Cup and Tashkent Open since transitioning onto the WTA tour.

What was different on Sunday was the decisiveness of the win, the lack of let-up as Potapova ruthlessly completed the upset in just over an hour.

The shift started in March; after losing back-to-back three-setters at the BNP Paribas Open and Miami Open (the latter despite holding four match points only to fall to Misaki Doi), Potapova parted with longtime coach Irina Doronina, whom she often called "a second mother."

She announced an impressive hire ahead of the clay court season, teaming up with Iain Hughes. Having worked with the likes of Elina Svitolina and Belinda Bencic, the experienced Brit has impressed on Potapova the need for a more relentless on-court approach.

"The main thing that he’s telling me is that it’s not about quantity, but instead about quality. If I can keep the same high quality in the first two minutes of a practice and maintain that for 90 minutes, I can beat big players. This has really helped me."

Hughes' influence was apparent, both on court - where she threw herself into 28 blistering winners against Kerber - and also in our interview, particularly when the rising Russian explained the importance of focusing on what she can control - something Svitolina herself said verbatim after ousting Venus Williams hours later.

"We didn’t talk too much about Angelique, or even about the match. He said that I’m good enough to play on this court, and good enough to compete with these players. I just needed to believe, fight, and that was going to be the key."

Potapova will play Marketa Vondrousova on Wednesday, in search not only of her first win over the Czech youngster (she trails a combined 0-2 in juniors and seniors), but also a best-ever Grand Slam result as she plots a return back to Chatrier Court.

"Marketa is a very good player. She’s quite young as well, and I think it’s going to be a great match because the last time we played in Budapest, I was injured and I didn’t do too well in that match.

"This time, I’m much better prepared. I see she’s also in good shape, so I think it’ll be an interesting match. The only thing I know is that I’m going to do my best, and I hope that works for me."

Even with an expanded WTA vocabulary, the teenager remains very much herself, eager to celebrate her career milestone with a good night's rest and a dream doubles debut with friend and former junior rival, Internationaux de Strasbourg champion Dayana Yastremska.

"My favorite thing to do when I’m not playing is to stay in bed and sleep as much as I can! I like Paris and France in general, and even all of Europe. I enjoy playing tournaments here, visiting nice places, walking around, tasting coffee and macarons. It’s a great place to show your best tennis, and just enjoy life."