Adam Hose starred with the bat for Bears, hitting seven sixes in an innings of 65 as they made 179-6.
After losing their first three wickets for 28, Lightning staged a superb recovery with Glenn Maxwell and Keaton Jennings putting together a century stand which threatened to earn Lancashire an impressive victory.
However, Maxwell’s dismissal for 79, bowled by Will Rhodes, brought an end to those hopes.
When Jennings fell to Rhodes for 35, it sealed a much-needed win for Bears with the Lightning’s innings ending on 164-7.
Dom Sibley and Sam Hain staged an opening stand of 53 to provide the base for their victory as Bears produced an improved batting display.
Birmingham moved up a gear in the fourth over which produced 18 runs and they passed the 50 mark two overs later.
Leg-spinner Matt Parkinson claimed the first wicket of the day when he had Hain stumped after making 21.
Hain had been promoted to open the batting following his innings of 49 against Nottinghamshire and he scored a four and a six before departing.
Sibley continued his progress with two boundaries in successive deliveries beforer Liam Livingstone was introduced in the 11th over and was hit for two sixes by Hose.
Bears passed the 100 mark in the 12th over as Sibley reached 50 off 38 balls.
Hose had his eyes on sixes and he drove Maxwell to bring up the half-century partnership with Sibley.
Then Parkinson tempted Sibley into a shot which saw him caught by Steven Croft.
That signalled a wobble for Bears with Rhodes falling to Livingstone for a duck.
Hose put them back on track and brought up his half century with a well-placed four – the only one of his innings – and followed it up with two successive sixes.
Parkinson brought an end to Hose’s innings with the first ball of his return to the Lightning attack.
Livingstone then slammed the brakes on in the final over with two wickets in successive balls.
In reply, Lightning were reduced to 28-3 by the sixth over before Maxwell and Jennings steadied the innings in style.
Maxwell was the dominant batsman and he reached 50 with his sixth four of the day after facing 28 balls.
Maxwell then brought up a nine-over century stand when he pulled Oliver Hannon-Dalby for a six over square leg in an over that produced 22 runs.
Rhodes then produced the wicket that Bears wanted in the 16th over when he bowled Maxwell with Lightning on 135-4, still 45 runs short of their target.
Maxwell’s innings came off 39 balls and included eight fours and four sixes but the Bears claimed quick wickets after that and Jennings was unable to respond.