On a three-match winning run that included one in the AFC Cup, East Bengal rallied from one goal down as Dudu Omagbemi's 56th minute smashing header cancelled out Joshimar d'Silva Martins' 33rd minute penalty kick.
Nigerian import Martins, who was eyeing a record 200th goal in the combined I-League and NFL, struck a poor penalty that stayed low and went straight to the hands of Mumbai goalkeeper Nidhin Lal in the 73rd minute to shatter East Bengal's hopes.
Having dropped points at home, the result meant that East Bengal's title hopes virtually went up in smoke as they failed to move up the ladder and remained on fifth position with 20 points from 13 matches.
Eighth placed Mumbai FC (14 points from 14 matches), on the other hand, continued their winless run.
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The crowd included a handful of mediapersons and some members who were issued separate cards for the match.
East Bengal coach Eelco Schattorie rued the lack of home crowd in the match.
"There was little pressure on the players because of lack of crowd. Screaming supporters add up to the tension," he said.