“Aside from the strength of our opponents, they also have this incredible support that will cheer them on to the last minute,” Marotta told Sky Sport Italia ahead of the match with Dortmund.
“I have confidence, as the team is growing day by day, there is a clear upward trajectory and progress is made in every area.
“The team has shown maturity and organisation in every game, but also impressive football. They have been able to both take control and to fight back to earn a result, as they did last week in Bologna.
“Getting through the group stage of the Champions League would be like a diploma, confirming the work of these months has paid off.
“It remains the start of the journey and we are developing as time goes on, but it is still a slow progress, we need to eliminate certain errors and of course have a coach who is very demanding.
“Alexis Sanchez will be back in January and we’ll see him as a great new signing who can help us take a few steps up the ladder.”
Marotta also spoke to Sport Mediaset about the interest from Barcelona and Manchester United around Lautaro Martinez.
“We are Inter, a big club who do not necessarily need to sell our champions, unless they ask to leave. In Lautaro’s case, the clause is irrelevant, what matters is his desire to grow and improve along with his teammates.”