Last year at the US Open, Nick Kyrgios found himself embroiled in another controversy. Down two sets to one in his third-round match, Kyrgios abruptly retired, citing a hip injury.

This incident did not sit well with ESPN commentator John McEnroe, who did anything but mince words. "Nick Kyrgios, if you don't want to be a professional tennis player, do something else," McEnroe said on the broadcast. "He's hurt because he's not training enough."

But arguably the lowest point of Kyrgios' career came a little more than a month later, when the ATP suspended him for conduct contrary to the integrity of the game. The tour alleged that he failed to give full effort, i.e., tanking.

Maturity, smarter tactics and an unreturnable serve have led Nick Kyrgios to the best season of his career so far. David Aliaga/Actionplus/Icon Sportswire

At the time, the ban appeared to be little more than the next chapter in Kyrgios' disappointing existence as a professional tennis player. But here we are a half-year later with the French Open just days away, and the long misconduct narrative has given way to hope. His talent is now accompanied by a growing sense of maturity. And that maturation could be enough to see Kyrgios go far on the dirt of Roland Garros, and then a few weeks later, at Wimbledon where the Aussie has already made significant statements.

With two wins against Novak Djokovic this year and a stunning clash with Roger Federer at the Miami Open, where Kyrgios fell in three tiebreaks, he has showed how much his mental game has grown. In a decisive moment in that match, two points from victory, a fan yelled out as Kyrgios was about to serve. Kyrgios vented at first, but immediately cooled off and played his heart out. He ended up losing that battle, but the immediate takeaway was how well he composed himself until the final point.

"I had some ups and downs, a bit of a roller coaster," Kyrgios said to the press afterward. "Ultimately, I thought I put in a good performance."

That performance was largely a result of a nearly untouchable serve, but not a one-dimensional hit-it-as-hard-as-I-can delivery that top players eventually figure out.

"You give that guy an early break, man, you're goodnight Irene," ESPN analyst Brad Gilbert said. "That guy can close you out. I sat courtside when he played Djokovic in Indian Wells, and it was just absolutely a thing of beauty. Like a pitcher, he's got like the fastball, the curveball; he's got it all. His variety -- he can bring a 141 [miles per hour serve] and then he can hit a nasty kick. As a returner you're not sure what he's going to bring."

What he can also do is belt second serves harder than most players hit their first. In his two wins over Djokovic, in Acapulco, Mexico, and Indian Wells, Kyrgios, still just 22, won a combined 62 percent of his second-service points and faced only one break point in 23 service games. He varied his second-serve speed between 83 mph and 129 mph, the latter faster than any Djokovic first serve in that match.

As Craig O'Shannessy, an analyst for the ATP Tour, recently said: "Kyrgios is not simply bending the traditional second-serve rules of our game. He is breaking them in half. His slowest second serve for the match was followed by his fastest second serve for the match. Djokovic didn't know what was coming. It's that gap that really creates havoc. His strategy is as solid as a rock, so I give a lot of credit to his mind and his tennis IQ."

The ATP has a stat called serve rating, which is a complicated formula a la passer rating in the NFL, but it takes into account serving percentage, aces and double faults. Only two players, John Isner and Ivo Karlovic, rank higher among current players. As for Kyrgios' returns, he's converted 41 percent of his break points, an excellent number for a player who is not known for his defense.

Former world No. 4 Greg Rusedski possessed a wicked lefty serve. He compared the Kyrgios serve to that of a top-quality bowler in cricket, where no two deliveries are the same.

"He's a naturally gifted, intelligent match player as well, which he doesn't get enough credit for," said Rusedski, who will be covering the French Open for Eurosport. "You don't beat Djokovic back to back, whether he's playing his best or worst, probably the greatest returner of serve that we've had in the men's game. ... It shows you that there's a lot going on rather than just hitting the tennis ball.

We've wondered for years whether Kyrgios' adolescence would prevent him from living up to expectations. There isn't a rising player in the game, not Dominic Thiem, not recent Rome winner Alexander Zverev, who has the raw upside of Kyrgios. But leveraging that talent is another story. This season, after a disappointing start in the Australia swing, where he lost in the second round, Kyrgios has played remarkably well. He went 7-2 in the U.S. Masters swing, one of the most difficult parts of the season.

But his results aside, Kyrgios has been candid in his assessment of himself. His sentiments speak to where he is today and why we can't overlook him with Roland Garros around the corner.

"Last year, I didn't really know what I wanted out of the sport," Kyrgios recently said in a press conference in Madrid. "Some days, I didn't want to play. I think I'm trying to battle with that now. I think I'm doing a good job. I think this year I've kind of pulled it together mentally."

Said ESPN analyst Pam Shriver: "I think there have been some incidences that have forced his hand a bit. His girlfriend [WTA player Alja Tomljanovic] -- I know her a little bit -- is really level-headed, lovely young lady. Don't underestimate the influence of Ajla Tomljanovic in helping Kyrgios mature.

"He's still going to probably have some relapses in behavior, but I think they're going to be less and less, and I think we are going to see some brilliance, whether this year or next year he's going to get to a semi or a final [of a Grand Slam] and eventually win one, unless he just gets injured or he really can't find a way to put maximum mental effort into his tennis. Things are so going in the right direction for him. It's great for him; it's great for the sport."

Having made a late start to his clay-court season after the death of his grandfather, Kyrgios was beaten by Rafael Nadal in Madrid and then had to pull out of Rome because of a niggling hip injury, but expects to be ready for the French Open.

"He has the most talent of anybody 23 and under," Gilbert said. "I think he has the game to be a multiple Slam winner, but now I think more than anything, the one component he needs is to become more physically like a beast, because he gets nicked up a lot. I think when he gets stronger physically and can play week in, week out, that serve potentially is as good as it gets."