Dhoni (39 not out off 32 balls) and Negi (36 off 17) shared a 54-run stand and smashed 53 off the last five overs to push Super Kings to a fighting total after the hosts struggled for runs in major part of the innings.
The home team a had a rather a quiet start by the standard of their explosive openers as they reached 44 for one in the first six overs.
It seemed the New Zealander will make Mumbai pay for their mistake when he hit three successive fours off medium pacer Vinay Kumar. However, much to the relief of the visitors, the dangerous batsman was caught at deep mid-wicket the next ball after he mistimed another hit off the Karnataka bowler.
His opening partner Smith too was holed out at deep-midwicket, as well as Suresh Raina, who was sent back with a brilliant running catch by Hardik Pandya, leaving Super Kings at 67/3 in 10 overs. Pandya was the catcher in all three dismissals.
Dhoni now had Negi by his side and the Delhi based cricketer, coming ahead of Ravindra Jadeja, did not disappoint his skipper, smashing four fours and a six in quick time.
The captain too got into the groove late into his innings, collecting two sixes and as many boundaries to the delight of his fans at Chepauk.