Despite the loss of opener Lendl Simmons for a duck, Trinidad started positively with Evin Lewis’ 46-ball 62 helping his side build a healthy total before Yannick Ottley added 41 further runs to leave Trinidad 153 for five after 20 overs.
Mumbai responded through Smith and Tendulkar as they raced towards their target but the tie was still in the balance with two overs remaining.
But Dinesh Karthik smashed two boundaries at the start of the penultimate over to calm the nerves and struck the decisive maximum soon after to wrap up victory with five balls remaining.
“It was really a team effort,” said winning skipper Rohit Sharma.
“They [Trinidad] started really well, we didn't manage to pick up wickets early on. But, our bowlers did well to restrict them to 153.”
Man of the match Dwayne Smith added: “I just made sure that the team got off to a good start.
“The pitch was fairly two paced but it became easier and got a lot better after the first six overs.”