RCB chased down RR's target of 170 despite being 87/6 at one stage.
Chasing 170 to win, RCB needed 82 runs from the last 7 overs with only five wickets in hand but they overhauled the target with four wickets and five balls to spare.
The table turned in the 14th over when Dinesh Karthik slammed Ashwin for 21 runs. In the 15th over, Navdeep Saini conceded 16 runs as the pair of Karthik and Shahbaz Ahmed brought RCB back in the chase.
WATCH – “I made a conscious effort this year to do justice to myself”, says Dinesh Karthik
While Gavaskar criticized Samson's field placements, Shastri did not agree with the RR captain’s decision to give the 15th over to Navdeep Saini.
"Ashwin helped (Karthik with that no ball) because you give momentum to a batter who has just come into the crease. He got a free hit. If that wasn't the case then he might have thought twice about whether to play that shot or not but once you get a free hit, you can go for the boundary hit. Then he got another one and the momentum was with him.
"You go for 21 now what does the fielding side do at that stage. The immediate next over, you gotta go for someone who is your banker. And I thought Chahal should have bowled that over. Yeah (tactical error from Royals).
"You went to someone as inexperienced as Saini. Of the entire lot, the most inexperienced was Saini. He went for 17 and you were done and dusted.
“One just got the feeling that they (RR) just lost the plot. They didn't bowl to their fields. If fine -eg was up, they were being hit over fine-leg, if thirdman was up, the ball was squeezed through in that direction," Shastri said on ESPNCricinfo.
On the other hand, Gavaskar criticized Samson on-air when Karthik smashed Prasidh Krishna's fuller length delivery towards the deep mid-wicket area for a boundary in the penultimate over.
"Sanju Samson is answerable. Questions must be asked. No fielders in the deep on the on-side will always be easy picking for someone like Dinesh Karthik," Gavaskar said while commentating on Star Sports.
While Karthik remained unbeaten on 44 off 23 balls, Shahbaz Ahmed played a dazzling knock of 26-ball 45 as RCB secured a valuable two points with a hard-fought win.