The British No. 2 remembered seeing Alcaraz get frustrated during the Wimbledon final this summer, when he lost to Jannik Sinner in four sets. And he felt it was a similar story in Paris.

“I actually saw him when I came back from the bathroom after the second set, he was talking with his team, and he was not in a good place there,” Norrie told Sky Sports one day after earning the biggest win of his career.

“And I hadn’t seen that since maybe the Wimbledon final when I was watching it on TV and I was seeing him kind of talking with his team and I was not really sure, I’d not seen him like that.

“Usually he’s smiling, enjoying, and I didn’t see too much of that yesterday so I knew I had pushed him enough for him to be rattled. But he’s still No. 1 in the world, he still comes up with the most amazing shots.

“He’s one of my favourite players, so you have to respect him. I just tried to be ready and I didn’t want to let that influence my energy, I wanted to keep bringing point-for-point and bring my intensity.”

Norrie had previously beaten Alcaraz on two other occasions – but never when the Spaniard was ranked at No. 1 in the world. And the 30-year-old admitted he was feeling a little hungover on adrenaline after shocking Alcaraz in the second round.

He added: “I think last night was quite difficult to get some sleep. A lot of messages, a lot of adrenaline. Just tried to sleep as much as I can, and I feel like a little bit hungover from yesterday, but in a good way, a lot of energy this morning.

“It’s a great win but you need to bring it back. There’s no time to be thinking about how good the win was or whatever. Just let it go, and we take the positives from that and take the confidence, for sure, and go and attack the next guy.”

The tournament is only just beginning for Norrie, who now faces Valentin Vacherot in the last 16. Vacherot became the lowest-ranked Masters 1000 winner in history when he beat his cousin, Arthur Rinderknech, to claim the title in Shanghai as a qualifier ranked No. 204 in the world.

Now sitting inside the top 40, Vacherot beat Rinderknech again in the second round of the Paris Masters, and Norrie was keeping a close eye. “I watched the end of it. It was a battle, I think both those guys really wanted to win, it’s a huge match for both of them,” he explained.

“Vacherot is so impressive, he’s so, so confident right now. He’s hitting winners, he’s returning well, his backhand is not missing.

“I watched his first round against [Jiri] Lehecka, he played probably the match of his life, so he is playing the best tennis of his life, for sure. For me, I’m going to have to play my best to have a chance with him because his form has been incredible.”