Brazilian winger, Malcolm opened the scoring for the Spanish Champions after 83 minutes, curling beyond Samir Handanovic in the Inter goal.
But the hosts hit back straight away when Mauro Icardi pounced on a loose ball inside the Barca penalty area.
The result means Barcelona are now guaranteed to make it out of the group stages.
Inter remain in second position in Group B but have still to play Tottenham who came from a goal down in the group's other game Tuesday to defeat PSV Eindhoven 2-1.
Barca remained without record goalscorer Lionel Messi who was adjudged not ready to return from the fractured forearm he suffered against Sevilla in October.
However, the Catalan club still dominated their hosts for most of the match, denied on numerous occasions by the inspired Handanovic.
Luis Suarez and Philippe Coutinho were both kept at bay by smart saves from the giant Slovenian in the first half - a theme that continued in the second period until Malcom fired home.
The summer signing from Bordeaux has had a stuttering start to his Barcelona career but looked to have sealed the win for his new side until Icardi leveled.
That goal could turn out to be an important one for the Italian side given the late drama that saw Tottenham claim victory over PSV in London
Harry Kane scored in the 78th and 89th minutes to give Mauricio Pochetino's men a precious three points.
The Dutch side had led for most of the match thanks to Luuk de Jong's header in the second minute.
Inter remain three points ahead of Spurs heading in to game week five later in November when the two sides will meet in London - a fixture that could go a long way to deciding who accompanies Barca into the last 16.
PSG held by Napoli
Paris Saint Germain and Napoli played out an entertaining 1-1 draw that leaves Group C wide open going into the final two games of the group stage.
Juan Bernat scored just before halftime to put the Ligue 1 leaders ahead but Lorenzo Insigne equalized from the spot after Jose Callejon was felled by PSG goalkeeper, Gianluigi Buffon.