PARIS -- Separated by only 14 months, they’ve known each other since they were 10 years old. And now, nearly two decades later, Americans Danielle Collins and Madison Keys are enjoying some of their finest moments in tennis.

They’ve both experienced the zenith of reaching No.7 on the Hologic WTA Tour and, with a good run here at Roland Garros, can come tantalizingly close to that career-high mark, for Collins is ranked No.10 and Keys is at No.12.

In the 1951 classic, “An American in Paris,” Gene Kelly plays an ex-GI who remains in post-war Paris to become a painter and falls for the beguiling Leslie Caron character. Set to the Jazz Age music of the Gershwin brothers, the two leads dance their way through the entire film.

That’s kind of what’s happening with Collins and Keys in France.

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Keys was a 6-3, 6-2 winner over Renata Zarazua on Tuesday. A day earlier, Collins defeated fellow American Caroline Dolehide 6-3, 6-4.

On Wednesday, Collins meets qualifier Olga Danilovic and on Thursday, it’s Keys versus Mayar Sherif.

A week ago at the WTA 500 Internationaux de Strasbourg, the two good friends played in the final, and Keys was a 6-1, 6-2 winner.

“I never like losing in the finals, but if I’m going to lose to someone,” Collins said at the trophy presentation, “I don’t mind losing to you, because we’re American buddies.”

No one, quite frankly, saw this coming.

Collins was ranked No.54 and, after losing a second-round match to World No.1 Iga Swiatek in Melbourne, said she was planning to retire at the end of the season. Now she’s won 22 of her past 25 matches and titles in Miami and Charleston.

“I think there’s probably a reality of [Collins] is really enjoying herself out on the court right now,” Keys said. “With more wins, the confidence builds even more and more, and I think that’s when Danielle gets more and more dangerous. It’s been really fun to watch her do that."

Keys? She was out for five months with a shoulder injury and didn’t come back until March. Keys advanced to the semifinals in Madrid, the quarters in Rome and won her first clay title in five years at Strasbourg.

“Starting at Indian Wells, it’s kind of a hard time of the season to try to jump back into things and have some tough losses, tough matchups,” Keys said. “So being able to just kind of get some momentum in Madrid was really helpful and beneficial and just being able to win a couple of matches.

“It just seemed like from there everything just kind of became a little bit easier in a way, just getting another match and another match. That’s just really all you want when you feel like you're trying to catch up with everyone else.”

Since the Miami Open, they are a combined 37-7.

Before the tournament, 18-time major champion Martina Navratilova raved, understandably, about their games:

“Amazing, really, what Danielle Collins has done when you think about it,” she said. “I think coming out and saying she was retiring did free her. You know, `I’m not trying to figure out my game. There’s no long term -- it’s just now.’ Saying, ‘OK, what do I do really well? Let’s work on that. Let’s concentrate on the strengths.’ It’s been fun to watch. She just leaves it all out there.

“Those big hitters that made the quarters in Rome, watch out for them. Especially Madison. She’s not the most comfortable on clay, but on a given day she can hit anyone off the court. For her, it depends on the draw.”

Based on the seeding alone, Keys would advance to the Round of 16 where she’d play No.2 Aryna Sabalenka in an incendiary match that might require a local fire squad.

The good news? Collins and Keys wouldn’t have to play until they reach the final.

Collins’ next match won’t be easy. Only a month ago, she had to come back from down a set and a break to defeat Danilovic in a third-set tiebreak. The Madrid match ran 2 hours and 43 minutes and ended past midnight. It was Collins’ 14th straight match-win.

“Very different conditions, different court speed,” Collins said, referring to the altitude of Madrid. “Yeah, I think it will be a totally different matchup this week. But, obviously, she’s been playing some really great tennis and doing some great things out there and definitely pushed me and challenged me in the last match.”

Keys was dominant against Zarazua, winning 33 of her opponent’s 51 service points and breaking her seven times. Keys dictated policy most of the time, hitting 27 winners along with 27 unforced errors.

“Obviously, since she’s been playing on the clay, she’s been improving each week, which is really exciting to see for my friend,” Collins said. “I think Maddie is extremely dangerous and has the capability to keep excelling with her tennis and her career.

“Yeah, she’s proved that over the years that she’s one of the most dangerous players on tour."