It was Fikru Teferra who struck the first goal of ISL to give the home franchise a 27th minute lead to bring the 70,000 capacity crowd at the Salt Lake Stadium to their feet, while Borja Fernandez's stunning volley from the edge of the box delighted one and all with some top quality stuff.
Substitute Arnal Llibert (90+3rd) gave the Kolkatans enough reasons to celebrate by turning Fikru's cross from the right to give a perfect ending to the match of the league touted to change the landscape of Indian football.
From the short passing of ATK's to the trademark English style long passes by the MCFC, it was high quality football on display, something that was rarely seen at the Vivekananda Yuva Bharati Krirangan.
The iconic stadium might have witnessed such a big crowd during in the reminded one of an East Bengal-Mohun Bagan but the derby never had experienced such motley spectators who varied from hardcore football fans to young families to waving youngsters.
It was a day of many firsts at VYBK as fans enjoyed quality football with replays from 17 giant screens that dotted the uppermost tier, something that was never experienced in Indian football.
The 28-year-old Ethiopian forward got a long through pass from ATK's marquee player Luis Garcia and before German defender Manuel Friedrich could intercept, brilliantly chipped over local lad Subrata Paul for the first goal.
The home team had the better share of chances and Spanish short passing skill was well evident in the side which had its affiliations with La Liga giants Atletico Madrid.
Dominating the game in deft passing, ATK got two fine opportunities early into the game with Baljit Sahni missing a one-on-one chance with Paul in the ninth minute.
Garcia was involved in both the chances as the former Liverpool star first set up Sahni before his left-footed volley was saved by Paul in the ninth minute.
Mumbai tried to add sting to their attack bringing in Italian forward Andre Moritz in the second-half and he won a freekick at the edge of the box but only to put it away.
MCFC also had a narrow escape when their defender Raju Gaekwad got away from a second booking and possible red after a tough challenge.
Mumbai were hit hard by the absence of former France international Nicolas Anelka and injured ex-Arsenal and Sweden star Fredrik Ljungberg.
Atletico de Kolkata: Subhasish Roy Chowdhury; Biswajit Saha, Arnab Mondal, Denzil Franco, Jose Miguel Gonzalez Rey; Ofentse Nato, Joffre Mateu Gonzalez (Jakub Podany 62'), Luis Garcia (Arnal Llibert 87'), Borja Fernandez; Baljit Sahni (Sanju Pradhan 81'), Fikru Teferra Lemessa.
Mumbai City FC: Subrata Paul; Pavel Cmovs, Syed Rahim Nabi (Nadong Bhutia 40'), Deepak Mondal, Manuel Friedrich, Raju Gaekwad (Peter Costa 57'), Johan Letzelter; Tiago Ribeiro (Andre Moritz 46'), Jan Stohanzi, Lalrindika Ralte; Diego Fernando Nadaya.