However, needing to match or better Borussia Dortmund's score, the Italian outfit squandered a string of chances in the second half and saw three goals disallowed for offside before Ansu Fati came off the bench to snatch victory for Barcelona.
Find out how all of the action unfolded at the San Siro courtesy of Sports Mole's minute-by-minute updates below.
Barca travel to Italy having already secured top spot in the group, but for the hosts it is all to play for tonight as they look to beat Borussia Dortmund to second place. Dortmund will be favourites to beat Slavia Prague in the group's other game, which would mean that only a win will do for Inter if they are to avoid dropping into the Europa League.
It promises to be a fascinating night, then, and with only five minutes until kickoff let's waste no time by looking at the team news...
SUBS: Padelli, Politano, Dimarco, Lazaro, Candreva, Bastoni, Esposito
SUBS: Ter Stegen, Araujo, Suarez, Morer, De Jong, Fati, Busquets
Perez still has plenty to do, but he produces a really sharp finish to slide the ball home and stun the San Siro with only his second Barcelona goal.
I said a goal before half time would give them a lift and it certainly has, with Lukaku firing a deflected drive past Neto after the ball had dropped to him just outside the area. The celebrations are temporarily halted as VAR is checked, but confirmation comes and so does the fist pump from Antonio Conte!
At the moment that would be enough to see Inter through with Dortmund also drawing against Slavia Prague, but it is still all to play for in the coming 45 minutes.
Griezmann had fired the ball in towards the feet of Vidal, but Godin got in a foot in to prevent it getting to the Barcelona midfielder. Unfortunately for the former Atletico Madrid, the ball bounced straight to Perez, who swept his finish home.
Martinez held the ball up really well before teeing up his strike partner, who fired home via a slight touch to cap a superb minute for the hosts after Slavia equalised against Dortmund moments earlier.
The hosts have created sights of goal and look capable of getting another goal in the coming 45 minutes, so they just need to keep it tight at the other end too.
It is a clinical finish from the sub as he fires a low strike into the bottom corner off the post having seen the ball drop invitingly to him. Surely that ends Inter Milan's hopes once and for all?!
Antonio Conte's side lose 2-1 at home to a much-changed Barcelona side to finish third in the group, with only a victory enough to see them through tonight as Dortmund beat Slavia Prague. Lukaku levelled things up after Perez's opener, but the former United man missed some great chances and Inter also had three goals ruled out for offside as they fell short.
Thank you very much for joining Sports Mole for tonight's contest as Barcelona knock Inter Milan out of the Champions League with victory at San Siro. I will leave you with our match report, and be sure to stick around for reaction too.
From me, though, it is goodbye for now.