Indian Premier League side Mumbai defeated the Rajasthan Royals in the final of 2013 tournament, but their attempts to make the group stages of this year's competition got off to a poor start on Saturday.
Mohammad Hafeez won the toss and asked Mumbai to bat first and that proved to be a good decision as Lendl Simmons (7), Jalaj Saxena (0) and Ambati Rayudu (3) fell cheaply in Saturday's clash in Raipur.
Michael Hussey's 28 from 26 deliveries and a solid knock of 37 from Aditya Tare helped recover the situation to an extent, but Mumbai could only post 135-7 from their 20 overs, Aizaz Cheema and Wahab Riaz taking a couple of wickets each for the Lions.
In response, Nasir Jamshed (26) and Ahmed Shehzad (34) put on 51 for the first wicket, while Umar Akmal's electric 38 from just 18 deliveries included six boundaries, as the Pakistan side wrapped up victory with eight balls to spare.
Saturday's other qualifier saw Kane Williamson's quickfire half-century help Northern Districs beat Southern Express by seven wickets.
The match was reduced to a 10-over contest due to heavy rain and when play commenced a combination of Kusal Perera (37) and Danushka Gunathilaka (39) helped Southern Express start well.
The rest of the order failed to contribute, though, and Northern District were set a target of 93.
New Zealand batsman Williamson duly took things into his own hands, smacking eight boundaries on his way to 52 from just 29 deliveries.
Williamson was eventually bowled by Farveez Maharoof, but Northern District reached their target with three balls remaining.
"It was great to get off to a good start and get a win under our belt," Williamson said.
"When a game is shortened like that it brings lot more uncertainty into it. It was nice to come off winning at the end of it.
"There were probably a few nerves early on but it was great to find our feet and play with a lot of confidence."