Mercedes is keeping a watchful eye on protégé Esteban Ocon, but the young Frenchman needs to step up to the next level this year says Toto Wolff.
Ocon is considered by many as a potential contender for a seat at the plum Silver Arrows team in 2019, when Valtteri Bottas' contract with Mercedes expires.
A good performance by the Finn this season could warrant an extension of his deal however, while Red Bull's Daniel Ricciardo could also be lurking in the wings.
Ocon's performance since he started his career as a Grand Prix driver in 2016 with Manor has been highly impressive, both in terms of consistency and outright speed.
The 21-year-old finished 2017 hot on the heels of his Force India team mate Sergio Perez, but a sensational graduation to the world championship outfit will require a step up in performance this year.
"Esteban performed very well last year against a very strong Sergio Perez," Wolff told Motorsport.
"This year he has to take the next step and improve this performance. He is incredibly consistent, makes few mistakes and has great speed.
"This year, he will have to develop further in this respect and outperform Perez."
Ocon's fierce rivalry with his team mate in 2017, which was marked by several on-track clashes, drew the scrutiny of Wolff who admits to have been annoyed by the multiple flash points which occured between the pink panthers.
"What bothers us are these intra-team rivalries that end with two damaged cars," said Wolff.
"This applies not only to Esteban, but also to Checo [Perez]. As a team boss, I'm so annoyed by that."