Rafael Nadal and Novak Djokovic know better than to overlook Jannik Sinner and Lorenzo Musetti

PARIS -- The Italian word for party-pooper is guastafeste, which neatly describes what Jannik Sinner and Lorenzo Musetti will be trying to do when they take on Rafael Nadal and Novak Djokovic, respectively, at Roland Garros on Monday.

Top seed Djokovic and champion Nadal are on course to meet in the semifinals this year, one round earlier than in 2020, when Nadal thumped Djokovic to win the title for a record 13th time.

But Nadal and Djokovic know they will need to be on their toes from the start against the two 19-year-old Italians, each hugely talented, athletic and highly motivated.

"I know very much that he is a big challenge to me," Djokovic said. "So there is no question I have to go out playing on a high level, because, you know, he will not have much to lose. I'm sure he's going to come out and really try to play the tennis of his life playing on one of the two big courts."

Nadal knows all about Sinner, having played him in the quarterfinals last year, when the Italian had a set point in the opener, the only man all fortnight to get that close to taking a set off him.

Then, Sinner was ranked 75. Now, he's ranked 19th, with two titles under his belt and a belief that singles him out as a potential superstar. He trained with Nadal in Australia at the start of this year and pushed him hard when they played each other in Rome last month.

"Jannik is not the best fourth round, without a doubt," Nadal said. "He's a dangerous one. He's young. He's a great player. We know each other well. So let's see.

"He's improving every week. I need to be ready to play at very high level of tennis, to have chances to be in the quarterfinals, and I am going to fight for it."

And to think, Sinner could have picked skiing.

Born and raised in the South Tyrol region of northern Italy, Sinner was a champion junior skier at the age of 12 but chose tennis due to the lower risk of injury.

At 13, Sinner decided to leave his home in Sexten for Bordighera on the Italian Riviera and the tennis center run by renowned coach Riccardo Piatti, who worked with Djokovic when he was a teenager, and who has coached the likes of Maria Sharapova, Richard Gasquet and Ivan Ljubicic.

Sinner and Piatti are still together, and with his strong serve, aggressive all-around game and a seemingly unflappable temperament, he has moved smoothly inside the world's top 20. Now he's looking forward to another shot at the defending champion.

"In one way it's tough to play against [the top players]," Sinner said. "In the other way, I think it's good that we play against them. It's a good test [but] I have played twice already against Rafa. So this time is going to be a little bit different."

On his main draw debut at a Grand Slam, Musetti beat David Goffin in the first round -- just like Sinner did in 2020 -- and outlasted fellow Italian Marco Cecchinato in five sets to reach the last 16.

More flamboyant, with a one-handed backhand and game that looks perfect for clay, Musetti is different from Sinner in style and personality.

"Lorenzo, I think he's an incredible player," Sinner said. "Already, he can do whatever he wants with the ball. He has so many options.

"I think he's talented, very, very talented, I would say, maybe more than me. Physically he is very, very strong."

Musetti fell to the clay in joy at the end of his win over Cecchinato, the man who beat Djokovic at Roland Garros in 2018.

And though the world No. 1 has not dropped a set this year, Musetti said he might have a little inside knowledge.

"We practiced a lot with Djokovic together, so we know each other a little bit," he said.

"Never played and it's going to be the first time, especially in a Grand Slam, so for sure there is going to be a little bit of tension, but I think it's what I'm working for since my childhood. All the sacrifice and hard work I did in the childhood became reality now. So I'm just enjoying the moment and I will try to do my best."