Matej Poplatnik scored a brace (23rd, 55th minutes) to put Kerala Blasters in the driving seat.
Slavisa Stojanovic scored a 16th-minute penalty before a fabulous strike from Courage Pekuson handed Kerala Blasters a two-goal lead at half-time.
A fairly one-sided affair saw Gianni Zuiverloon scoring a fantastic goal while Rene Mihelic netted one from the spot.
The best moment of the half came towards the fag end when youngster Dheeraj Singh proved his worth with a brilliant save.
Mumbai inched to within three points of league leaders Bengaluru FC, while Kerala Blasters remained eighth.
Kerala Blasters have been winless at home this season and have not picked up full points since their opening round win against ATK.
Carlos Calvo put Jamshedpur ahead in the 66th minute before Seiminlen Doungel's equaliser in the 77th minute ensured the spoils were shared.
Chennaiyin FC are now placed eighth in the league with just five points from nine matches.
NorthEast United's are now placed third on the ISL table with 14 points from seven matches.
Bengaluru FC's Sunil Chhetri sustained the injury during an Indian Super League match against Kerala Blasters.
Bengaluru FC kept their perfect record.
Kerala Blasters were handed their fourth successive draw.
Matej Poplatnik made the most of a deflection off Gerson's foot to nod home the first goal in the 77th minute.
ATK will renew acquaintances with two-time runners-up Kerala Blasters
David James was the player-manager for Kerala when ATK triumphed in the inaugural edition, and since then his record against their rivals hasn't really been encouraging
The fifth season of the ISL will see 10 teams compete for the coveted crown.
David James was the marquee manager for Kerala Blasters in the inaugural edition of the Indian Super League.