Top coach and Tennis Channel expert Paul Annacone runs the rule over the two clashes.
Annacone marvels at Rafa's ability to 'stay in the moment'
Acclaimed coach and commentator breaks down Wednesday's quarter-finals for rolandgarros.com
Nadal v Schwartzman (head to head: 10-1)
Schwartzman famously broke his duck against Nadal when he beat him in the semi-finals in Rome last year, but the Spaniard got his revenge at the same stage at Roland-Garros soon after, on his way to his 13th title in Paris.
Wednesday’s match is going to be played in the warmth of the afternoon and Annacone says that just gives Nadal an even bigger advantage.
“I do think the conditions are going to be unfavourable for Schwartzman. If it's warm and the ball's real bouncy, that's much better for Rafa," explained the American.
"And Rafa doesn't need many benefits as is. So I think it's going to be important early on for Schwartzman to find a way. It sounds crazy, to find a way to hold serve. I think he'll probably find ways to get in the return games, but he's going to have to work so hard, I just think it's a really tough environment if it's warmer and lively.”
Annacone said he continues to be impressed at how Nadal manages to peak at this time of the year, every year.
“Rafa is so amazing in that he has such a great ability to stay in the moment. And I think, in his heart of hearts, in the rare time where he does actually have to dig deep, you know, the experience of winning so much helps, but he doesn't have to do it that much. And yet he also just stays in the moment. I think it's pretty honourable," Annacone added.
"I mean, if you're a coach, you're like, 'how do I teach someone to do that? How do I teach someone that really all that matters is the next 10 seconds and then just do that over and over and over again?'.
"But yet if you start to lose, have the confidence to know that you have done this all in the past. He does that balance quite magically. And it's pretty amazing to watch.”
Djokovic v Berrettini (head to head: 1-0)
Berrettini enjoyed an extra day off after the withdrawal of Roger Federer but the Italian -- contesting his first Roland-Garros quarter-final compared to Djokovic's 15 -- has a tough task to break down the resilience of Djokovic, who is trying to close the gap between himself and Nadal and Federer to just one at the top of the men's all-time Grand Slam titles list.
Annacone said the fact that the match is being played at night – with 5,000 fans – could help the Italian, thanks to his weapons.
“Berrettini has got the firepower to cause problems,” he said. “But you saw yesterday with Novak [against Lorenzo Musetti], he's locked in and he doesn't get emotional and kind of overbearing on himself that it's a tough win, except that Berrettini's serve is huge and his forehand is huge.
“Berrettini's had a day off, we always talk about, is that good or is it bad?... but I would think this is a good opportunity for Berrettini at night because he has enough power to hit through the conditions anyway.
"But for Novak, he's such a great defender, it's hard to figure out how to finish points unless you're 19 and have a one-handed backhand and you're Italian (like Musetti, who won the first two sets before fading in their fourth-round clash).”
Annacone said it might help Berrettini to add some variety to his game, which is mostly based on his big serve and massive forehand.
“Musetti showed us what you can do to cause Novak a little bit of imbalance and Berrettini doesn't really do that much. He’s more of a bludgeoner. He can take the hand off the racquet and use some slices, I think we’ll probably see some of that. But he does have enough firepower to cause problems," he concluded.