Sri Lankan star Kumar Sangakkara scored a stylish 94 from 56 balls to help the Kings XI register a competitive 182 in match 10 of the IPL.
In reply Aussie speedster Brett Lee's opening burst put the Kings in the drivers seat, a position they never relinquished.
The Kings running out comprehensive 66 run winners and keeping the Mumbai Indians winless.
Mumbai join the Deccan Chargers as the only teams without a win in three matches.
Sangakkara's 94 makes him the leading run scorer in the tournament, ahead of New Zealander Brendan McCullum
Following the match Punjab bowler Sreesanth was spotted in tears after an incident with Harbhajan Singh.
It is alleged that stand-in Mumbai captain Harbhajan Singh had struck Indian team-mate and IPL rival Sreesanth in the face.
Kings XI Punjab v Mumbai Indians
Punjab 10/182
Bat:
Kumar Sangakkara (SRI) - 94 (56)
Yuvraj Singh (IND) - 18 (9)
Karan Goel (IND) 18 (21)
Brett Lee (AUS) - 16* (8)
Ball:
Harbhajan Singh (IND) - 3/32
Ashish Nehra (IND) - 2/22
Dhawal Kulkarni (IND) - 2/37
Mumbai 9/116
Bat:
Dwayne Bravo (WI) - 23 (21)
Shaun Pollock (RSA) - 22 (21)
Robin Uthappa (IND) - 21 (18)
Luke Ronchi (AUS) - 11 (8)
Ball:
Irfan Pathan (IND) - 2/19
Piyush Chawla (IND) - 2/16
Sreesanth (IND) - 2/31
Brett Lee (AUS) - 1/9
Player of the match: Kumar Sangakkara (Kings XI Punjab)
Kings XI Punjab won by 66 runs