Mohun Bagan emerged winners with second-half goals from Joseba Beitia and Nongdamba Naorem just two minutes apart.
The green and maroons had the lion's share of possession and more shots on target but the home side had more attempts and five more corners in a game which could have gone either way.
Bagan coach Kibu Vicuna started with newly-signed Senegalese striker Babacar Diawara and brought in Dhanachandra Singh in the backline with Gurjinder Kumar who was suspended.
Scotsman David Robertson, the RKFC coach, however, preferred the same starting eleven which won against reigning champions Chennai City in the previous game.
The visitors were strong from the starting whistle and notched up as many as three corners in the space of the first six minutes.
Talented winger Nongdamba Naorem then had his first chance of the game when it opened up for him inside the Kashmir box in the 22nd minute, but his left-footer failed to cause any problem for Phurba Lachenpa in the Kashmir goal.
Both sides got golden chances to score but the first half remained goalless.
In the second half, while Bagan continued to dominate possession, the home side had the better scoring chances in the opening 20 minutes.
Then Sankar Roy brought the save of the game in the 65th minute to deny Mason Robertson with his header from close, off a Higginbotham set piece.
By now, Kashmir had thrown in Ivorian striker Gnohere Krizo in the mix and had stepped up their attacks. However, it was the visitors from Kolkata who turned the match on its head within a space of two minutes.
First, of a long Dhanachandra Singh throw from the right-flank, Daniel Cyrus somehow managed to deflect the ball in the path of an onrushing Beitia. Beitia positioned his body perfectly to meet the loose ball with a right-footed jab, which powered its way through to the Kashmir net. The ball went in off the keeper and Bagan were 1-0 ahead with 71minutes on the clock.
A couple of minutes later, another young Bagan talent Sk. Sahil showed an outstanding vision to find substitute PM Britto's run down that same flank with a wonderful through ball. Britto rushed in clear and floated the ball back in. Naorem, who had an outstanding game, was at the end of this one and blasted a perfectly-connected volley into the back of the net. 2-0 Bagan.
Kashmir did make valiant attempts to come back and Loveday Okechukwu perhaps missed their best chance to come back with less than five minutes to go. Krizo too had an attempt from close but it was going to be Bagan's day to celebrate.
Francisco Morante, for his robust defensive display in the heart of the Bagan backline, was adjudged Hero of the Match.
Bagan now have 10 points from five games while Kashmir drop to eighth with five points from four games. The Mariners will now host Indian Arrows on January 9 whereas the Snow Leopards will host Punjab FC one day later.
( With inputs from IANS )