Earlier this week, Federer said: “To win a Grand Slam, you have to play far more offensively. The title doesn’t just come to you.

“When I watch him play, I see someone who plays far too passively, far too defensively in the decisive moments. Against the best players in the world you have to take the initiative and play offensively. He didn’t do that against Fritz.”

But Zverev didn’t bemoan the 43-year-old for his opinion. “That’s nothing I don’t know,” he confessed. “It’s absolutely clear to me that I didn’t play the way I wanted to play. That was a terrible game from me. That’s why it’s completely okay what Roger said.”