Speaking to DAZN before the champions' big match against Napoli, Marotta was keen to broaden the conversation beyond a straight fight between the two heavyweights.
"It's not just Napoli and Inter for the Scudetto — there's a whole group of teams that includes Roma, Juventus and others like Como too. The final verdict is very much undecided," he said.
"There's an awareness that winning is difficult, but retaining the title is even harder. We have to be conscious that we haven't achieved anything yet, and we need to rediscover the motivation that has to stay with us, because we are the team to beat and the challenges have only increased."
Asked whether Federico Dimarco and Hakan Çalhanoğlu would be renewing their contracts, Marotta struck a measured tone about the club's approach to its key players.
"We have a lot of respect for all our players, and we'll shortly begin talks with their agents to see what their requests are," he said. "As I always say, if a player shows a strong sense of belonging, I believe that value should be respected as we assess together how to continue the relationship."
The Inter Milan president also confirmed reports linking Lautaro Martínez with a move to Barcelona, while making clear the club's position was never in doubt.
"Yes, that's true, but our response was very firm," Marotta said. "And the player himself expressed his wish to continue with us — he's our captain, he represents Inter's history, present and future, so long may he continue."
Marotta's comments come with Inter looking to build on last season's title defence and reassert themselves as Serie A's dominant force, even as a congested table featuring the likes of Roma, Juventus and surprise package Como threatens to make this campaign considerably more competitive than the last.
The Nerazzurri's growing reputation as the team every rival wants to beat has clearly not been lost on their president, who used the platform to remind supporters and players alike that nothing has yet been secured this season.