Philippe Coutinho has been told to “not even think about joining another club”, with the Barcelona playmaker urged to ignore interest from the likes of Manchester United by Blaugrana legend Hristo Stoichkov.
The Brazil international has spent just 12 months at Camp Nou.
He completed a big-money move from Liverpool in January 2018 and was expected to become a key creative influence alongside the likes of Lionel Messi, Luis Suarez and Ousmane Dembele.
Coutinho has struggled for consistency at the Liga giants and seen his value and ongoing presence called into question as a result.
A return to England has been mooted, with United said to be keen after Jurgen Klopp moved to rule out a possible second stint at Anfield.
Stoichkov, though, believes that the 26-year-old can prove his worth at Barca, with the iconic Bulgarian striker writing in an open letter published by Mundo Deportivo: “I am writing these words to send you my most sincere support for the difficult moment you have been going through, although I'm sure there are a lot of players out there who would like to be in the same situation as you like when you scored those two vital goals against Sevilla in the Copa del Rey.
“And by the way, for the first goal, to have an incredible player like Messi asking you to take that penalty - a penalty which set the course for the rest of the tie. That's a task that only the very best players are asked to do.
“Barca isn't an easy club and during my first few months there, I suffered like you. I know how it feels when things aren't turning out how you want, but I'm convinced that with hard work and sacrifice you'll move forward because you have all the quality you need to do that. You are one of the best foreign players to have played for Barca.Getty Images
“You've got a lot of football in you to give Barca and the only thing you should be thinking about is enjoying your game. Enjoy it like you do with Brazil. I tried to enjoy playing like I always did with Bulgaria and I ended up enjoying myself exactly the same with Barca.
“Never let yourself be disheartened because, from what I've seen, the fans are with you and want to see you succeed. Understand that they're the best fans in the world and they'll support you always - like they did with me.
“And besides, now's not the time to feel down, we have every reason to feel positive. Forget all about the draw against Valencia. It's starting to get tight at the top in La Liga, the Champions League is back and more than anything, we are about to face a month in which we'll have three games on the trot against our eternal rivals, Real Madrid, who we can never rule out.
“The Clasico is the best game in the world and you yourself know what it's like to score in one - it's a feeling which cannot be matched. We'll need you at your best to sew up the league and book our place in the Copa del Rey final - and even more so if the God of Football, Leo Messi is carrying a groin strain from the Valencia match.
“Lastly, a small favour. Please do not even think about joining another club, which is something I've read might happen in the press. There is no other club like ours. That's why they say it's more than a club. And anyway, you wouldn't find another club with mates like Messi, Suarez and Co. with whom you have a great time doing what you love most - playing football.
“I wish you all the best, with all of my heart, I am sure that you will make history at Barça. Keep your chin up! A big hug, Hristo.”
Coutinho has recorded eight goals and five assists this season, but more is expected of a man snapped up in a deal which could end up being worth €145 million (£127m/$166m).