Playing at home, Mascarenhas bowled a deadly spell, claiming five wickets -- Sourav Ganguly (16), Marlon Samuels (2), Robin Uthappa (17), Mithun Manhas (31) and Rahul Sharma (2) after Punjab won the toss and inserted the visitors.
There was a hint of movement in the wicket after overnight rains and the hosts made good use of it as they bowled a good line to make life difficult for Pune, who had beaten them in their first leg match.
Middle-order batsman Manhas was the top-scorer for Pune and his 28-ball innings included three hits to the fence and a six, but he also fell to Mascarenhas in the 18th over while trying to play a sweep shot over the short fine-leg region.
In the same over, Rahul became Mascarenhas' fifth victim when he had him caught by Mandeep Singh. Ashok Dinda was the last man out when he was found short of wicket in the last ball of the 19th over.
Earlier, Pune suffered an early blow when New Zealand's Jesse Ryder (7), who tried to steal a cheeky single, was run out in the third over.
However, it was Mascarenhas who dealt the massive blow when in the 6th over, he had Ganguly caught by Shaun Marsh of the leading edge. The former India skipper's nine-ball innings was laced with three fours.
Mascarenhas then struck again in the same over when he had struggling Samuels bowled out on an incoming delivery.
