Chasing a stiff 192, Kings XI Punjab were 96 for no loss in 8.2 overs, with a required run rate well in excess of eight runs.
But when play resumed after a 95 minutes' rain delay, KXIP needed just 29 off 28 balls in the revised DLS target was 125 in 13 overs. The visitors sealed the issue with 11 balls to spare.
"Suddenly after rain, they needed run-a-ball. I didn't understand that bit but I am sure Duckworth-Lewis is something people are still trying to figure out what it is," an irritated Karthik said at the post-match news conference.
"That was little surprising, because ideally if it would have been a 20-over game, they would have needed eight an over. If we could have got two quick wickets, the run rate would have kept going up."
The IPL is played under ICC's Playing Conditions with DLS being the recognised system but Karthik feels BCCI should use Jayadevan rule which is known as VJD.
"I have always thought that the VJD is an Indian method and it's an Indian domestic tournament, why not think about it in the future?" he asked.
"It's been proven that it's a really good method. We have used in domestic tournaments. Only for IPL, we use DLS. Why not think about VJD here and promote it?"
It must be mentioned in this regard that Jaydevan had made presentations to ICC but it has been rejected.
Conceding that they bowled poorly, the KKR skipper believed that their target was par, even as they fell 10-15 runs short with just 11 runs coming from last two overs.
"We could have scored 10-12 runs more. But more importantly we did not bowl good enough to defend it."
Gayle again stood tall with a blistering 62 not out from 38 balls as it was his third fifty-plus score in a row in their hat-trick of wins.
"There is not a pattern to get him (Gayle) out that teams have found out yet. He's batting really well and you got to accept that. It's not only Chris Gayle's day but KL (Rahul) also did well."
KKR's big hitting batsman Andre Russell pulled his hamstring and was taken off after failing to complete the fourth over but Karhik said he seemed fine.
"I've not spoken to him but he looks okay for now."
First Published: April 22, 2018, 7:50 AM IST