Barca looked set for the victory that would have confirmed them as Group B winners when substitute Malcom put them ahead with a strike in the 83rd minute, two minutes after coming off the bench.
Mauro Icardi then equalised in the 87th and the visitors’ 100 per cent start in the pool to an end.
While Barcelona are through with 10 points from four games, second-placed Inter have seven points and Tottenham, up to third after beating PSV 2-1, have four.
Lionel Messi was once again not involved, having missed Barca’s previous four matches. Messi, who has been recovering from a fractured arm and returned to training last week, had travelled with his team-mates to Italy but was not included in the matchday 18.