Barcelona will have to wait to book their place in the Champions League knockout stages after Mauro Icardi's scored a late equaliser to earn Inter Milan a 1-1 draw at the San Siro.
The Spanish champions went ahead late in the game when substitute Malcom made an instant impact, firing home just minutes after coming onto the field.
However, a spirited Inter side drew level just four minutes later when Icardo capitalised on some questionable defending, lashing into the net from inside the area.
Inter will travel to Wembley Stadium on matchday five to face Tottenham Hotspur, who sit just three points behind them in Group B.
Barcelona, who were without the injured Lionel Messi, got the better of Inter in the reverse fixture, two weeks ago, and made one change to the team that won 2-0 at the Nou Camp.
The visitors went close to breaking the deadlock inside two minutes. Ousmane Dembélé's curling effort was parried away by Samir Handanović.
Visitors dominate the first-half
Ivan Rakitić latched onto a poor goal-kick on 12 minutes, played the ball back up to Luis Suárez, who struck inches over the crossbar from the edge of the area.
Inter’s first real opening arrived seven minutes later when Ivan Perišić drove into the byline, from the left, pulled the ball back before Kwadwo Asamoah fired over the crossbar.
It was a glorious opportunity for the hosts to break the deadlock, but Barcelona were unfazed and continued to pass the ball around freely and dominate possession.
Suárez went close on 22 minutes when he chested down Jordi Alba’s pass and then lofted the ball over the ‘keeper and inches wide of the post.
The Uruguayan international struck off target after the half-hour mark, but the Catalan giants closed out the first-half strongly.
Philippe Coutinho’s low effort was drilled across the surface and pushed away by Handanović on 37 minutes.
Barcelona continue to press for opener
The Inter ‘keeper continued to frutrate the visitors. Three minutes before half-time, Coutinho’s shot was blocked in the penalty area before Suárez’s rebound was saved well.
Stefan de Vrij’s header sailed off target after the restart, but Barca picked up where they left off and continued to press for the opener as Coutinho was denied by Handanović.
On the hour mark, the visitors should’ve found themselves ahead. Suárez played the ball through to Rakitić, who had a clear sight of goal, but his strike ensured the Inter 'keeper had a straight-forward save.
Inter broke forward with pace on 65 minutes. Perišić drove down the left before delivering a cross and the advancing Matteo Politano could only guide his header wide.
Malcom's first Barca goal cancelled out by Icardi
Time was starting to tick away from both sides as they entered the final stages minutes of the game, however, Barca broke the deadlock on 87 minutes.
Coutinho carried the ball forward from the halfway line and found substitute Malcom, who shifted onto his left foot before whipping the ball into the bottom corner.
The Brazilian’s first ever goal for the Catalan giants was short-lived though as Inter drew level just four minutes later.
Matías Vecino's effort was blocked in the area, the ball came to the feet of Icardi, who turned and fired into the net to level for the hosts.
The striker had been starved of service all evening and with his only real chance, he found the back of the net to snatch a point for Inter.