An innings of 122 off 60 balls by Hong Kong No. 3 Babar Hayat - the fourth highest score in T20Is and the best by an Associate player - would normally have been the biggest talking point on most days, but it was Oman left-arm spinner Aamir Kaleem who provided that by mankading star batsman Mark Chapman prior to delivering the final ball of the ninth over of the Hong Kong chase. Oman went on to win the game by five runs in an eventful Asia Cup debut for the Persian Gulf state.

At the end of an action-packed and immensely tight game that went to the final over, the two sides took opposing views on the mankad. Kaleem said he had seen both batsmen leaving their crease too early more than once and decided to run them out if they attempted to do so again. But Hong Kong coach Simon Cook said mankading without any warning was a "cowardly act".

"Yes it's in the laws but I think it goes against the spirit of the game when you're not at least giving a warning," Cook said. "Ultimately it's a cowardly way out really, if you're battling against one another, man against man, out in the middle and you choose to go down that route to get a wicket and win the game, it's not really in the spirit of cricket."

First, Oman made excellent use of a batting track to post 180 but it began looking light when Hayat took charge in pursuit of the target. The match had been in the balance when the incident took place.

Oman had just picked up their second wicket in the previous over, but Hong Kong had put on 77 runs and needed 104 more from the remaining 67 balls with Hayat set on 57. It was then that Kaleem got into his delivery stride, pulled out, turned on his heel and under-armed a throw at the non-strikers' end to catch Chapman out of his ground.

Chapman waved his hands in disbelief for a moment, but walked off once the on-field umpire upheld Kaleem's appeal. Everything was legal as per ICC regulation 42.15 which says, "The bowler is permitted, before releasing the ball and provided he has not completed his usual delivery swing, to deliberately attempt to run out the non-striker."

There is no ICC regulation demanding courtesy a courtesy warning, referenced by Cook, but it has been common practice for a bowler to warn the non-striker who is straying out of his crease. Kaleem argued that it is the batsman's job to know better than to make such errors.

"No, I didn't [warn Chapman]," he said. "As a batsman, if I am non-striker, I know if I leave the crease before the delivery, bowler can do the same thing. I had just noticed two or three times that both batsmen - Babar was also doing it - so I just thought if they did the same thing, I would do this.

Kaleem also brought up the example of West Indies U-19 seamer Keemo Paul's actions in their victorious campaign at the Under-19 World Cup. In a must-win group stage match, Paul mankaded the last man standing Richard Ngarava for Zimbabwe as he ran up for the first ball of the 50th over with the opposition needing three runs and sealed West Indies' progress into the quarter-finals.

"We have all seen it happen in the Under-19 World Cup so it is not a wrong thing. It is under the rules. If the batsman goes before the ball has been released, any bowler can do this. So I did this."

It wasn't Kaleem's first mankad either.

"Five or six months ago, when we were in Nepal playing against Malaysia, their batsman was also doing the same thing. Our coaches have told us if they are doing the same thing [and backing up prematurely], go ahead and run the batsman out."

Alagappan Muthu is a sub-editor at ESPNcricinfo