Bengaluru posted 187-9 after Cameron Green hit an unbeaten 24-ball 32 and bowlers then combined to bowl out Delhi for 140 in 19.1 overs at their home M. Chinnaswamy Stadium.
Bengaluru, who moved to fifth, have mounted a late charge to make the play-offs but will need to win their last league match and other results to go in their favour to be in the top four.
Delhi slipped to sixth and go into their final match with 12 points. Bengaluru have also 12 points from 13 matches, but boast a better run-rate.
In the first match of the day, skipper Ruturaj Gaikwad led holders Chennai Super Kings to a five-wicket win over Rajasthan Royals and boost their play-off hopes.
Chennai moved to 14 points and third place with seven wins in 13 matches.
Rajasthan remain second in the 10-team table led by Kolkata Knight Riders, who are the only team to have already qualified for the next stage.
The top four teams will make the play-offs with the final on May 26 in Chennai.
In match two, star batsman Virat Kohli took charge after he smashed 27 off 13 balls to lay the foundation of Bengaluru's total in a match where Delhi missed skipper Rishabh Pant, who was suspended after a slow over-rate offence.
Kohli remains the leading batsman this season with 661 runs including one century and five half-tons.
Patidar, who hit 52, soon took control in a 88-run stand with England batsman Will Jacks, who smashed 41, before a late charge by Green.
Delhi faltered in their chase after they lost David Warner for one off left-arm spinner Swapnil Singh.
Left-arm quick Yash Dayal took down Abishek Porel and then ran out Jake Fraser-McGurk in successive balls and soon Delhi slipped to 30-4.
Stand-in-skipper Axar Patel put up a fight with his 57 off 39 balls but fell to Dayal in the 16th over and the wheels came off the chase.
Australia's Green took a wicket and ran out Tristan Stubbs to add to his batting cameo.
In the earlier match, five-time champions Chennai restricted Rajasthan to 141-5, a total they overhauled with 10 balls to spare in their last home game at MA Chidambaram Stadium.
Gaikwad anchored Chennai's tricky chase as they lost wickets at regular intervals including when Ravindra Jadeja was called out for "obstructing the field".
Jadeja was sent back by Gaikwad while attempting a second run and he changed direction on the pitch when the throw from wicketkeeper Sanju Samson hit his hand and the third umpire ruled him out after an appeal from the opposition.
Gaikwad kept his cool and put on an unbeaten 24-run stand with impact substitute Sameer Rizvi, who hit the winning boundary.
