After alternating victories in the first four races of the season, Verstappen secured the win at the Miami Grand Prix and went on to claim all Red Bull victories for the remainder of the season.
This led former driver Klein, who partnered with David Coulthard at Red Bull, to claim that Verstappen's victory in Miami broke Perez's mentality.
“I would say Max is definitely one with the car and with the team. It feels like pressure is not getting into his head at all,” said Klein to RacingNews365.com.
“That was the difference to Checo. He had a very good start to the season and maybe he had in his mind, ‘OK, maybe this year I can beat Max or at least on the same level’. But I think Miami was already the turning point where he realised, ‘OK the guy on the other side of the garage is really unbeatable’.
“I think mentally that broke him a little bit. It took him a really, really long time, maybe until the last couple of races where he got back [on track]. He's not a bad driver and you cannot unlearn how to drive a car fast. But in the end, it’s a mental game.
Klein also shared his belief that Perez's mentality now revolves around 'enjoying' his time at Red Bull rather than directly competing with Verstappen.
“I think he realised now that he’s at the end of his career,” added Klein. “He’s in the best team, in the best car. He realises ‘I have a driver next to me that I probably cannot beat’. [But he can] enjoy it, go for podiums and go for race wins. I think he was already thinking this way during the last races of 2023.”
Perez's 2023
Despite finishing second the drivers’ championship, Perez finished 290 points behind his team-mate Verstappen in first.
This sparked significant speculation about Perez's future at Red Bull, especially given that he was in the same car but struggled to compete at the top level.
However, even though the team has chosen to retain Perez for the 2024 season, Red Bull team principal Christian Horner issued a warning to Perez regarding his seat beyond next season.
“Checo works best when he is under pressure, that is what I have seen with him during his time with us," Horner told Sky Sports F1.
"You know, he is in the seat, it is his seat to lose and I think there is nothing pre-established for 2025, and we need him at full speed in 24 races next year to accumulate points and achieve victories."