The Catalans head into the group stage opener without star forward Lamine Yamal, who is sidelined with a groin injury. The 18-year-old, already regarded as one of the brightest talents in world football, has been instrumental in Barca's strong start to the season but will not travel to St James' Park.

Rashford, who joined Barcelona on loan from Manchester United this summer, is now expected to play a more central role. The 27-year-old endured a difficult spell at Old Trafford under Ruben Amorim but has shown flashes of his old form in recent weeks, scoring for England in a 5-0 World Cup qualifying win over Serbia before providing an assist in Barca's 6-0 rout of Valencia on Sunday.

Flick said he has long admired the forward's qualities. "I have really followed Marcus since he started at Manchester and I always said, 'Wow, what kind of player he is'. He is unbelievable. He has speed but also in one-against-one situations, he is fantastic and his finishing is excellent," the former Bayern Munich coach explained.

"What I have seen in the first weeks here is really good. I think he has more potential to show and he wants to do this. For me, it is great to have him in my team."

Barcelona last lifted the Champions League trophy in 2015 and Flick admitted there is huge pressure to end that drought. "Everyone wants to win the Champions League, and here in Barcelona the expectation is very clear. We will work every day to improve, and we will see what happens at the end of the season," he said.

Along with Yamal, Barca will also be without Alejandro Balde and Gavi for the trip to Tyneside, leaving Flick with limited options. However, he stressed that the squad remains strong enough to compete at the highest level.

Newcastle, returning to the Champions League for the second consecutive season, are expected to provide a stern test after strengthening their squad in the summer.

For Rashford, this match represents a chance to reignite his career on the biggest stage. Whether he can deliver in Yamal's absence could shape Barcelona's early push for European glory.

Hansi Flick backs Marcus Rashford to shine for Barcelona in clash with Newcastle