They are level on points with Inter Milan who host unfancied PSV Eindhoven, so Spurs need to equal the Italian side’s result to go through. Also, even though Ernesto Valverde had said earlier in the day that Luis Suarez will be rested after recently returning from injury, the indications are that Barcelona will put out a strong side, even though they have won Group B comfortably.

Pochettino is not fazed by throwing a youngster into a sink-or-swim scenario, and he has a remarkable track record in bringing out the best in young players, as Harry Kane, Dele Alli, and Harry Winks can testify.

Also, as Pochettino pointed out, Walker-Peters was in England’s U20 World-Cup-winning side last year, so he should not be overawed by the big stage.

“This is his opportunity for him,” said Pochettino. “Remember, he won the U20 World Cup and his quality is unbelievable. You need to trust young players and give them their chance. To play in the Nou Camp will make him strong, stronger than before and we don’t have doubts about him.

“Kyle has the quality. Most importantly, we trust in him whatever happens tomorrow. He will be a success, for sure, in the long term for this club. He’s a relaxed player and person.”

The Spurs manager was also relaxed enough in his press conference last night to joke that it was a good omen that one of his predecessors, Harry Redknapp, had been crowned King of the Jungle in TV’s I’m A Celebrity, Get Me... Out Of Here!

“Congratulations to Harry,” he said laughing. “That’s a trophy for us, no?”

Pochettino can afford to be relaxed, because the pressure is off his side. Anything other than defeat here would be a surprise and making the last 16 would be a minor miracle, considering Tottenham made such a mess of their opening three games that they were bottom of the group until last month.

Losing to Barcelona at Wembley was no disgrace, even if the manner and margin of defeat was more comprehensive than the Argentinian would have liked. His compatriot Messi tore them apart that night in October and has the ability to do it against the best sides, as he showed again at the weekend with two goals against local rivals Espanyol.

Hugo Lloris faces the task of trying to keep out Messi’s trademark free-kicks, he and said it was not about one player trying to keep the Argentinian superstar quiet.

“We have to defend against him as a team and, if we succeed, it will be as a team.”

Pochettino is very much at home in Barcelona, where he keeps a house from his days as a player and then later as manager of Espanyol, Barca’s city rivals who were crushed again in last weekend’s derby.

“Sometimes I escape from London to come to this magnificent city, a city I relate to,” he added.

Asked if it would be special for him to achieve qualification to the last 16 in his second home and against Barcelona, he said: “No, it would be special because it would be Tottenham qualifying for the last 16, not because I am an Espanyol fan!”

He is fully aware Spurs have made life difficult for themselves by conceding late goals to lose in Milan and draw in Eindhoven, but for those late lapses, they would be through.

“We deserved more against Inter and PSV in Holland. We didn’t need to have everything at stake in Barcelona, but it’s not about what you deserve, it’s about scoring goals and competing for 90 minutes.”

On the plus side, Tottenham have their big beasts fit and firing in attack, with Kane and Alli likely to be supported by Christian Eriksen and Heung Min Son. The only previous time those four started together this season was the 3-1 demolition of Chelsea that took Spurs back into the top three of the Premier League, but this will be another test completely.

“The quality Barcelona have is unbelievable. They are one of the best teams in Europe and the world. Our philosophy is always to dominate the opponent, just as theirs is, so it is difficult to challenge a team like Barcelona.

“But I’m optimistic. We are going to be ready to compete in our best condition. We must always believe we arrive at our best. It is a must-win game, so we need to give our best and prepare physically and tactically.”