Kolkata - owned by La Liga champions Atletico Madrid - will face Kerala Blasters at DY Patil Stadium in Mumbai on Saturday after prevailing on penalties against FC Goa.
Spot-kicks were required to determine a winner after two consecutive goalless and Kolkata emerged triumphant 4-2 following unsuccessful attempts from Goa pair Andre Santos and Zohib Islam Amiri on Wednesday.
Kolkata head into Saturday's showpiece fixture in the midst of a seven-game winless streak, having lost two matches and drawn five.
However, former Liverpool star and Spain international Luis Garcia insisted Kolkata are worthy finalists.
"We have been in the first position for 10 games," Luis Garcia said.
"It's true that we were struggling in the middle of the competition but after that, I think we didn't have to show anyone that we are the one of toughest teams in the competition.
"We showed that it's very hard to beat us and that we are a very good team. That's why we deserved to be in the finals."
"We need players who are at 100 per cent on the pitch and I definitely wasn't after that," Luis Garcia added.
"Besides, now there's a big game in a couple days and I intend to be fit for that one."
David James' Kerala required extra time to win 4-3 on aggregate after the second leg finished 3-1 in Chennaiyin's favour.
"As an avid football fan I think any team that wins a trophy has to have an element of luck," said James.
"But I wouldn't say that we were lucky; obviously, the sending off was lucky for Chennai, but our team fought really hard and once again, we have injuries going into the final; so that's going to be a concern."
Saturday's final pits teams against each other with similar records in attack and defence.
