Thomas Tuchel says Marcus Rashford has the potential to become one of the best forwards in world football, but is concerned the Barcelona loanee could waste his talent.
The England head coach has also revealed he talks to Rashford regularly, warning him that he needs to score more and create more, otherwise he might regret missed opportunities when he is in the latter stages of his career.
Rashford has recorded three goals and four assists in his 10 appearances for the Spanish giants since leaving Manchester United on a temporary move this summer.
"He can be one of the best in the world because the finishing and the quality I see in training, with both legs and his head, he is explosive, he is fast, he is strong in the air, so for him there are no limits," Tuchel said.
"But the numbers don't reach the potential. He needs to push himself with goal involvements. He knows that from me.
"I think he still has to make these decisions. He is still young enough to make these decisions, because otherwise he might be disappointed in 10 years with what he could have been and what he may have done.
"That is the headline for him, to keep pushing himself to the limit. And the limit for him is very, very high, maybe higher than it is for others.
"He has this potential. But potential is a dangerous word with high-level sports, because you have to reach your personal best on a regular basis - that is demanded on this kind of level and that is the challenge for him. It is not a question of talent.
"It is a question of whether he can prove the point at club and international level; this is his task. If he starts fast or if he comes off the bench, he has to constantly prove himself."
Rashford has been named in all but one of the squads Tuchel has opted for since his first game in charge back in March, with the summer internationals against Senegal and Andorra being the only games he has missed after picking up an injury to end the 2024/25 campaign while on loan at Aston Villa.
"I can feel him, and I felt in my first camp, I can help him if he feels my support for him because he was at Aston Villa at the time, which I thought was quite a bold move at the time, to go into a team that was well settled and played a hard-working style," Tuchel added.
"That was a very good move for him, he settled in very quickly. I liked his work rate against the ball, and still he had not as many goals and goal involvements as he could have, for the quality we see in training."
Rashford came off the bench in England's 3-0 win against Wales last time out, replacing his former Villa team-mate Ollie Watkins following an injury, and could get his next opportunity to impress against Latvia on Tuesday.
Kane set to return against Latvia
The Three Lions can secure World Cup qualification with a win and will be boosted by the return of captain Harry Kane, who was an unused substitute against Craig Bellamy's side after missing training due to an ankle injury in the build-up to the friendly.
"Very easy with Harry, he can play and is fit. We did the right thing," Tuchel said in his pre-match press conference.
"Top in training and ready to go. I don't see why he should not be able to play 90 minutes. I don't see any obstacles."
On Watkins, who went off injured against Wales and withdrew from the England squad as a result of the setback, Tuchel added: "Ollie [Watkins] left camp, unfortunately.
"It was too painful and could not train with us. He is in treatment with his club.