Inter Milan captain Lautaro Martinez did not hold back after Monday's 2-0 loss to Fluminense, criticising a lacklustre display as they exited the Club World Cup in the last 16.

Inter were stunned by a resilient Fluminense side, with the Italians failing to pose a real threat until the closing stages, leaving striker Martinez frustrated as he called on his teammates to show greater commitment.

"I want to fight for the major titles. Anyone who wants to stay at Inter, fine, let's fight. But anyone who doesn't want to stay can leave," the Argentine told reporters.

"We need players who want to be here. We're wearing an important shirt. We need a top-level mentality, or please leave."

Inter arrived at the revamped Club World Cup as title contenders but, aside from a 2-0 win over River Plate in the group stage, the Serie A side had an inconsistent campaign —beating Japan's Urawa Red Diamonds with a last-minute winner and being held to a 1-1 draw by Mexican side Monterrey.

Their last-16 exit adds to a frustrating season in which they failed to win domestic silverware and were crushed 5-0 by Paris St Germain in last month's Champions League final.

"It was a long and tiring season, we finished empty-handed. It is a general message," Martinez added.

"In order to stay up there and fight for titles, we must be eager ... I apologise to the fans who came here to follow us closely. I am the captain and I want to keep things at the top."

Inter will kick off their Serie A campaign at home to Torino in August.