Ander Herrera has sounded a warning to Kylian Mbappe by reminding him that Lionel Messi is the top dog at Paris Saint-Germain.
Messi, 34, arrived in the French capital on a free transfer from Barcelona this summer and his start to life in a PSG shirt has been mixed.
The Argentina captain has contributed six goals and four assists in 16 games in all competitions, with his finest performances coming in the Champions League.
Messi is yet to find his prolific best form in Ligue 1, whereas Mbappe has excelled for Mauricio Pochettino's side in domestic competition.
The French World Cup winner has an impressive tally of 13 goals and 12 assists in 23 games this season, leading to growing suspicions Messi could be passing the baton to a teammate over a decade his junior.
Join the debate! Is Messi still a better player than Mbappe? Have your say here.
Lionel Messi vs Cristiano Ronaldo: Records, goals and trophies won compared
However, PSG midfielder Herrera has rubbished these claims and insists the whole squad views the seven-time Ballon d'Or winner as "number one".
"Kylian will be the best player in the world for many years to come, but we all agree that Leo is number one. No doubt," the former Manchester United midfielder told Mundo Deportivo.
"Mbappe has an immense humility and desire to learn from Leo."
Herrera was also keen to emphasise Messi has not struggled in France despite his underwhelming return of one goal and five assists in Ligue 1.
"Players of Messi's level shorten the acclimatisation time," the 32-year-old added. "He will play the same way in France, in Spain, in Japan or in Madagascar.
"He has won his seventh Ballon d'Or and trains and enjoys as if he were only starting to play now. No training action is taken as a joke.
"At times we have already seen the best version of Leo, as against [Manchester] City at home, but I think it is also the responsibility of all those around him.
"We have to put ourselves at his service to get the best out of him.
"Normally, regular players have to adapt to a new context. Now it is the other way around because we are talking about the best footballer in history."
Herrera's comments on Messi and Mbappe come at a time of great uncertainty surrounding the latter's future.
The former Monaco forward is out of contract at the end of the season and he is heavily-linked with Real Madrid, who bid twice for him last summer.
But Herrara still hopes Mbappe could extend his contract, declaring: "We have many examples of footballers who have done it in February, March or April."
