Red Bull Racing team principal Christian Horner has no doubts his driver Max Verstappen will top Mercedes' list if world champion Lewis Hamilton decides to retire.

"Max will undoubtedly be the first choice when Lewis says goodbye," Horner said at a press moment on Monday.

"However, there are alternatives to Mercedes. They have George Russell and other drivers will also be available."

36-year-old Hamilton signed a new contract with Mercedes last week after months of rumors about his future, but for only one year.

Mercedes team boss Toto Wolff emphasized when announcing the news that both parties intend to continue with each other beyond 2021, but the short deal has fueled speculation that the seven-time world champion will start his final season next month.

In 2022, everything will be different in Formula 1 anyway due to a major change in the technical rules.

In addition, Verstappen has a clause in his contract with Red Bull until 2023 that he can leave after this season, allegedly if his team does not compete for the world title.

"It's all about relationships and producing a good car. That's going to be the deciding factor, not all kinds of clauses in Max's contract," Horner said.

"We have a very good relationship with Max and have to make sure that the conditions are ideal for him."

See also: Analysis: Hamilton's one-year contract with Mercedes favorable to both parties