PARIS -- Standing five feet behind the baseline and swaying ever so slightly, Coco Gauff stared intently across the net. The offering came from Dayana Yastremska and Gauff drilled it, forcing a weak, net-bound forehand from the Ukrainian.

It was Gauff’s second service break in four chances Friday and essentially locked down the first set. Her 6-2, 6-4 victory sent her flying into the second week at Roland Garros -- and had her nasty return game to thank.

The No.3-seeded Gauff won five of Yastremska’s nine service games (56 percent), against a player who reached the Australian Open semifinals as a qualifier earlier this year. In three matches here, Gauff’s a sizzling 15-for-25.

“It’s something I worked on,” Gauff said earlier this month in Rome. “I feel confidence in the way I work. I think if you work hard, you’ll get the results.”

Nobody, it turns out, is better at breaking serve right now than Gauff. The serve is the most important shot in tennis, the first strike of every point. If you can take that advantage -- take the racquet -- out of the hands of the server, you are way ahead of the game.

Gauff, incredibly, does it nearly half of the time. She’s winning more than 49 percent of her return games; next in line is World No.1 Iga Swiatek, at around 47 percent.

And while aces and offense get most of the attention, the best players understand the importance of many happy returns. Novak Djokovic is widely viewed as the best returner in men’s history, a significant factor in his record of 24 Grand Slam singles titles. Gauff’s enlightenment came from a 23-time major winner.

“One thing I learned from Serena [Williams], she would spend probably like an hour sometimes literally just hitting returns,” Gauff said. “I took inspiration from that because that’s the first part of the point. I think the average rally is like four or five balls. The first two balls are really important.

“For me, returns were something I was working on a lot because my return-made percentage honestly used to be really, really bad like a couple years ago. I’d be curious to look at those stats.”

In fact, Gauff finished the 2022 season with a return-games-won percentage of 34.8, which improved to 41.2 percent in 2023. Part of the reason was the addition of Brad Gilbert to her coaching staff last summer. One of the first things he did was move her back about eight feet from her original returning position.

“When she would play up on the baseline,” Gilbert said, “she would miss one or two returns a game. I think allowing her to have more time opens things up and takes advantage of her strengths. She makes way more returns and uses her movement and her ability to defend and play offense.”

The results were immediate. In the span of a few months, Gauff won her first WTA Tour 500 (Washington, D.C.), 1000 (Cincinnati) and Grand Slam (US Open).

Gauff said she’s had more success since realizing that every shot doesn’t have to be a return winner. She shortened her swing a touch and also keeps it hot by constantly moving her returning position.

“It’s not a huge [adjustment] that I made,” Gauff said. “I think it came with just reps.”

Having a terrific return game has benefits beyond the scoreline. It gives Gauff confidence while she’s tinkering with her service game. For while she’s at the top in returns, her service-games won percentage is under 70 percent -- in the mid-20s among Hologic WTA Tour players. By contrast tour leader Swiatek is well over 80 percent.

Against Yastremska, Gauff won seven of her nine service games but it was her constant returning pressure that made the difference. Yastremska, increasingly frustrated, finished with 38 unforced errors.

Gilbert is encouraged by Gauff’s progress and hopes she can find a serve/return balance like Djokovic.

“My favorite guy is Djoker,” Gilbert said. “Because he’s efficient. You look at his box score and he’s efficient, not flashy. Efficient is genius.

“When Coco gets the serve game going, then we’ll be fine.”