Sinner won 6-1 6-2 to secure his latest title with a dominant display in the Spanish capital.
And Zverev, who has lost to the Italian in semi-finals at ATP Masters 1000 events at Indian Wells, Miami and Monte-Carlo this season, was magnanimous in defeat.
“I think there’s a big gap between Sinner and everybody else right now,” Zverev said. “It’s quite simple.
“And I think there’s a big gap between [Carlos] Alcaraz, myself, maybe Novak [Djokovic], and everybody else. I think there are two gaps right now.
“It’s difficult to say that there’s not a gap between Sinner and everybody else if he hasn’t lost a match in Masters events since Shanghai.”
While Zverev spoke highly of Sinner, he described his own performance as “awful.”
”He’s very good, of course. But I think today I would have lost to anybody, to be very fair. I think today I played an awful tennis match,” the German said.
”I think everybody’s struggling against him. He’s won the last five Masters events, so it’s not like I’m the only one losing to him. I’m just losing to him more because I get to him every single time and I lose to him.
“So, it’s like that. Today doesn’t make sense to talk much about strategy, it was absolutely a terrible match by me. I don’t think there’s much strategy involved.”
Sinner is the first player ever to have won five consecutive Masters 1000 titles and if he wins the upcoming Italian Open, he will join Novak Djokovic as the only players to have won all nine of the ATP Tour’s main events.
”I think he’s very stable,” Zverev added. ”He doesn’t have dips, he doesn’t have phases where he goes down. I think that’s why he’s world No. 1. To me, that’s more spectacular, I think, keeping the level the whole time.”
World No. 3 Zverev, who is 7155 ranking points behind No. 2 Carlos Alcaraz and 8545 behind Sinner, will hope to go one better in Rome.
Sinner, meanwhile, will be the favourite to win yet another title as he builds towards the French Open later this month – live on TNT Sports and HBO Max – in ominous form.
”I think you win matches before matches,” he told Sky Sports after the Madrid Open final. ”I try to put the right preparations in and I’m very careful about what I put in my body.
”When I’m serving well in fast conditions like this, it helps. Starting with a break right away against Sashca is a good start. He didn’t play his best and was a bit tired, but I played well.”
He added: ”I’m very happy that I’ve continued to believe in myself. I’m showing up every day, at every practice session, trying to put in the right work with the right discipline.
“To do so, you need to have the right team behind you, which I have. I’m very happy about me, but also the team, and this means a lot to all of us.
”I know we are doing something incredible, so thank you so much. Thanks for standing by my side, I know that maybe a lot Italians are watching so thanks for the support at home, I really feel it.”