A Bernard Mendy header in the 33rd minute opened the scoring and John Stiven Mendoza netted home a second in the 48th minute for the hosts. For Pune, Kalu Uche scored in the 74th minute.
With the win, Chennaiyin are now in the second spot with three wins and three losses with nine points behind leaders FC Goa. On the other hand, Pune are now in third spot with nine points from five matches, having lost two and won three.
The hosts broke the deadlock in the 34th minute when a long throw from Dhanachandra Singh found Mendy, who did well to get past Nickey Shorey and made no mistake in striking the ball at the back of the net to help his team go 1-0 up.
Colombian star Mendoza doubled the lead in the 48th minute, racing on to an Elano Blumer through ball, rounding Steve Simonsen and finishing it at ease.
Pune pulled things up in the 74th minute with their first goal from Uche. But the only goal from visitors were not enough to ensure them full points as the hosts’ strong defence held Pune till the final whistle.
Chennaiyin next face Kerala Blasters FC on October 31 in an away match, whereas Pune take on FC Goa in an away match on October 30.