Du Plessis (54) and the league's leading scorer Virat Kohli (47) gave Bengaluru a strong start and their middle order followed suit to steer the team to a commanding 218-5 in their final group match.
Chennai managed 191-7 in reply in the rain-affected match as Bengaluru joined Kolkata, Rajasthan Royals and Sunrisers Hyderabad in the playoff.
"It felt like a day-five test match," du Plessis said explaining how difficult the pitch was to bat on after rain interrupted play.
"For me and Virat to just get through it and find a way somehow...and then in the back end to get a 200-score was unbelievable."
Middle order batters Rajat Patidar, Cameron Green, Dinesh Karthik and Glenn Maxwell produced breezy cameos to take Bengaluru past the 200-mark.
"That's been our last six games, hasn't it? Contributions from many batters with good intensity and good strike-rates," player-of-the-match du Plessis said.
"At the beginning of the season, we felt like we were a little slow and we wanted a bit more intent in our batting innings. And to have done that again is awesome."
Published 19 May 2024, 05:32 IST