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The Italian was inspired playing against his lifelong idol, pouncing on every Djokovic error to oust the three-time champion.

“He’s my idol, he’s always been,” Arnaldi said of Djokovic after the win.

“I was just glad that I could play him. I never played him, just practised with him. To play him at a stage like this was already a victory for me. He’s not at his best right now, so I came on court to try to play my best tennis and win, and it happened, so right now I don’t even know what to say.

“I was just trying to rally a bit at the start, trying to make him [make] some mistakes. Then once it starts, you start to feel better, the tension goes a little bit away.

"He gave me a little bit in a few games. For sure it helped me that I broke him straight away so I was like, ‘All right, that’s a good start’, and then after that, it was an escalation. I started to play better and I think it became a quite good match.”

Djokovic, the No.4 seed in Madrid has now suffered three consecutive defeats.

He reached the Miami final before falling to Jakub Mensik and then lost to Alejandro Tabilo in his Monte-Carlo opener.

The Serbian is still aiming to win his 100th ATP Tour title, but now has a 12-7 season record as the wait goes on.

“I was hoping I can play one more match than I played in Monte-Carlo," Djokovic said.

"[It’s] kind of a new reality for me, I have to say. Trying to win a match or two, not really thinking about getting far in the tournament … It's a completely different feeling from what I had in 20-plus years of professional tennis.

“It’s a challenge for me mentally to really face these kinds of sensations on the court, going out early now regularly in tournaments.”

Djokovic had not suffered three consecutive defeats since 2018, but has now done so twice in 2025.

“Obviously after you lose a match you don't feel good, but I've had a few of these this year where I lose in the first round, unfortunately,” Djokovic added.

“I knew that it was going to be a really tough opening match for me in this tournament. Arnaldi is a really good player, a quality player.

“I didn't have too many matches on clay. I did practise well, but it's completely different when you step out on the match court. I think the positive thing is that I really enjoyed myself more than I [did] in Monte-Carlo, so that's a good thing. But obviously the level of tennis is not where I would like it to be.

“But, that's the circle of life and the career, eventually it was going to happen.”

Arnaldi next faces Damir Dzumhur, who overcame No.32 seed Sebastian Baez 1-6 6-1 6-2.