The only goal of the match was a superb effort in the 79th minute by Syrian Mahmoud Al Amna, who positioned himself perfectly to meet a cross from the left which he blasted home with an angular drive beating MFC keeper Laxmikant Kattimani all ends up.
Only a little while earlier had the foreigner missed a golden chance to break the deadlock by shooting wide a gilt-edged pass, but made amends with his match-winning goal, off a pass provided by under 22 wing back Lalruatthara.
Aizawl, in fact, deserved the victory as they showed more attacking instincts and combined better than the hosts.
Jayesh Rane worked tirelessly in the midfield for the team from the north east. The visitors, coached by Khalid Jamil who was MFC coach last year, totally dominated the second half after having the better share of the proceedings in the first.
The victory was the third in a row for Aizawl who had beaten newcomers Minerva Academy 1-0 and then fellow-north easterners Shillong Lajong FC 2-1 prior to that after having held formidable Eat Bengal to a 1-1 draw.
The win also took their points tally to ten and moved up to third on the table. The loss, the second successive one for MFC, coached by Santosh Kashyap, following their 0-3 rout by defending champions Bengaluru FC in a previous away game, kept the home team down to fifth with six points from four games.
MFC had started the season with back to back wins over DSK Shivajians and Churchill Brothers before losing to Bengaluru.
The Mumbai outfit started with a packed defense and they were made to put in extra efforts and they did well to arrest the flow of attacks from the Aizawl forwards.
The Mumbai frontline also made a couple of raids towards the rival goal with Thoi Singh going wide from close and later his teasing cross from the right was comfortably collected by Aizawl custodian Albino Gomes.
The faster Aizwal attack came close in the very second minute when Albert Zohmingmawia sent a low ball across the Mumbai FC goal, but Bayi Kamo blasted over from just outside the six yard box.
Later the Mumbai goalkeeper Kattimani parried over Albert's snap shot from the right in the 26th minute.
Goalkeeper Kattimani once again came to the rescue of his team as he charged out in the nick of time to foil Mehta after the latter had latched on to Rane's defense-splitting through pass in the 34th minute.
Crossing over it was the visitors who looked better and better before they finally broke the deadlock and then kept the lead intact till the end.