Kolkata: United SC pipped Gokulam Kerala by a solitary goal in the 123rd IFA Shield at the Kalyani Stadium here on Sunday.
Middelton scored the winner in injury time as Gokulam got off to a losing start in the three-team Group D.
Gokulam next take on BSS Sporting on December 12. The two-top teams will advance to the quarterfinals.
Real Kashmir pulled off a comeback 2-1 win against Peerless SC in Group B at the East Bengal ground.
A solid build-up play by Sujay Dutta and a strong header by Uttam Rai gave Peerless a 20th minute lead.
Real Kashmir stepped up their attack and Danish Farooq first set up Chesterpoul to find an equaliser in the 25th minute before finding the back of the net in the 32nd minute to seal three points for his team.
Real Kashmir will next play Aryan Club at the Kalyani Stadium on December 9.
At the Mohun Bagan ground, Indian Arrows were held to a 1-1 draw by Southern Samity in a Group C fixture.
Sujit Saren put Southern Samity in the lead against the run of play in the 27th minute, but the AIFF developmental outfit fought back in the second-half to level the scores with Gurkirat Singh's 79th minute strike.
Fresh from their promotion into the I-League, Mohammedan Sporting began with a thumping 4-0 win over Kiddirpore SC 4-0 in Group A at the Saltlake Stadium.
(With inputs from PTI)