Carlos Alcaraz considers "dangerous" Jannik Sinner as the world's best player and the man to beat at the Madrid Open.
Sinner has won three titles in 2024, including his maiden grand slam crown at the Australian Open, and is the top seed in the Spanish capital.
Novak Djokovic is absent from the Masters 1000 tournament but will remain the top men's player regardless of how far Sinner advances.
And while the Italian's only appearance on clay this year saw him lose to Stefanos Tsitsipas in the semi-finals of the Monte-Carlo Masters, Alcaraz knows full well what he is up against should the pair cross paths.
"He's dangerous. He's the best player in the world right now," Alcaraz said in his pre-tournament news conference.
"I think [some people] think his tennis doesn't suit well to the clay, but he has had results on clay as well.
"He can win every tournament he goes to, and obviously I'm fighting with him and with Novak to be world number one. I'm trying to stay there, but honestly it is going to be difficult."
World number three Alcaraz was unable to compete in Monte-Carlo, as well as the Barcelona Open, due to an arm injury.
However, the Spaniard is relishing the chance of returning to clay-court action on home soil when his pursuit of a 14th Tour-level title begins against either Arthur Rinderknech or Alexander Shevchenko on Saturday.
"For me, it's really important to be at 100 per cent here in this tournament," he said. "Playing here is so special.
"It's the tournament where a lot of family can come to watch my matches, a lot of friends as well, and for me it's really special to play in front of my home crowd as well.
"I would love to play at 100 per cent just to give them the opportunity to enjoy my tennis and give myself the chance to get a good result here."
Alcaraz is aiming to become the first player to win three successive Madrid Open crowns and is on a collision course to meet Sinner in the final.
The 20-year-old ended Sinner's winning streak with victory in their BNP Paribas Open final showdown last month, with that a rare blemish for the latter.
While Sinner has been the best male player this year, boasting a record of 25 wins to two losses, he believes there is still room for improvement.
"I don't want to put pressure on myself," he told reporters ahead of the tournament. "I'm living a very positive moment, winning a lot of matches.
"I just try to keep going like this. In my mind, I know that I can and have to improve if I want to win more.
"I am searching for new opportunities and I feel like that every tournament I play, there can be a good opportunity trying to show that my level has raised.
"Showing what I have improved and that's for sure something that I would like to do here. This is a new opportunity, new tournament and we'll see how it goes."