Mumbai Indians captain Rohit Sharma took a liking to the medium pace of Abu Nechim as he smashed three sixes in one over in his attacking 15-ball 42.
The loss of Parthiv Patel didn't deter Mumbai Indians, who were boosted by a 72-run stand between Simmons and Unmukt Chand, back in the team after replacing Vinay Kumar.
David Wiese, on IPL debut, starred with the ball for RCB with figures of 4 for 33 that included the wickets of Parthiv Patel, Kieron Pollard, Rohit Sharma and Ambati Rayudu.
Simmons had departed for 59, but Unmukt carried on and raised his maiden IPL half-century before departing for a well-made 58 off 37 balls.
After a horrible start to their season, Mumbai Indians began on a strong note with openers Parthiv Patel and Lendl Simmons getting the team off to a strong start after by put into bat by Royal Challengers Bangalore.
When AB de Villiers walked in, RCB needed a superhuman effort and the South African was off the blocks immediately.
The second ball of 15th over got de Villiers on strike again but the batsman found Kieron Pollard at long on off Jasprit Bumrah after scoring 41 off 11 balls.
The sequence of AB de Villiers' innings went like this: 4, 6, 4, 4, 1, 6, 6, 2, 4, 4 and RCB began to dream again.
Gayle's dismissal was closely followed by Virat Kohli's dismissal for 18 meant RCB had fallen behind by a huge margin, having reached 60 at the halfway stage, needing another 150 from the next 10 overs.
Harbhajan Singh's three wickets for 27 runs put the skids under RCB that included the wickets of Bisla, Gayle and Rilee Rossouw.
David Wiese's dream debut in the IPL continued as he kept RCB in the game by clobbering 47* from just 25 balls but his team still fell short by 18 runs.
Chasing a mammoth 210, Royal Challengers Bangalore may not have got their batting combination right and chose Manvinder Bisla to partner Chris Gayle at the top, but the move backfired. After Bisla's early dismissal, Gayle was unusually circumspect and fell after scoring a 24-ball 10.