Former F1 star Juan Pablo Montoya has warned Ferrari boss to expect a 'personality clash' between Lewis Hamilton and Charles Leclerc from next year.
The F1 grid is set to look drastically different next year with Hamilton starting a domino effect after announcing an agreement to join Ferrari.
The seven-time world champion is hopeful the move can help restart his career with Mercedes falling down the pecking order in recent years.
He's still regarded as one of the best drivers on the grid and he'll go toe-to-toe with Leclerc to be Ferrari's No 1 driver.
Montoya feels that will inevitably lead to clashes between the pair as they find their footing as partners.
Lewis Hamilton will team up with Charles Leclerc from next year
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"It will be interesting to see how smooth that goes with Charles and Lewis in the cars, to be honest," said Montoya, speaking to RacingNews365.
"There's going to be a personality clash there. It's going to be fun to watch.
"But Vasseur doesn't appear concerned of any dispute between Leclerc and Hamilton.
Speaking earlier this month, the Ferrari boss stated his confidence that Leclerc will benefit from having Hamilton alongside him in the garage.
"Even for Charles, having Lewis there will be very useful.
"He is a monster in terms of organisation and approaching the race.
"He will raise the level of our demands and preparation.
"I feel he [Hamilton] wants to win so badly. Lewis is an excellent motivator.
"It's not just a question of setting a faster lap time. It is also about knowing we have 1,500 people who want to compete because he is there, because he pushes, because he will not settle for the first best answer he gets."
Hamilton's upcoming move to Ferrari has made Sainz a free agent heading into 2025 and is arguably the hottest driver on the market.
Fred Vasseur will need to work out a way to get both drivers on the same wave length
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Mercedes have been linked with taking Sainz, but Montoya feels Red Bull will be the Spaniard's best option.
"I think Carlos right now would be the best choice in my opinion [at Red Bull], especially if there's talk of Max leaving," he said.
"If they're thinking about Max leaving, they need to have an A-plus driver as a back-up.
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"You can't have Checo and Max leave because then you have nothing.
"But right now he (Sainz) is doing the job. He's doing what needs to be done.
"Could there be better drivers? Probably. But I think in the right situation, Carlos can be really good."