Williamson was ruled to be one over short of their required over-rate target, after time allowances were taken into consideration. He pled guilty to the offence, which was dished out by the match umpires, and was fined 20 per cent of his match fee.
However, most concerningly for the New Zealand squad, Williamson is now running the risk of being suspended. If the Black Caps commit another minor over-rate offence during the World Cup - in a game with Williamson at the helm - it will be deemed a second offence, and he will receive an immediate one-game suspension.
According to the ICC Code of Player Conduct, a second minor over-rate offence carries a fine - 20 per cent of the match fee per over short of their target - and the "imposition of a suspension for the immediately subsequent international match, in the same format of the game as that in which the offence occurred."
Such a breach is extremely rare for New Zealand, having only been fined for over-rate offences nine times since 1992. At the other end of the scale, Pakistan have been fined a remarkable 96 times for the same issue, while India have been pinged on 77 occasions.
Under Williamson's reign, the Black Caps have been caught short just once - in the 2017 Champions Trophy match against England, where they were two overs short of their required rates.
Williamson's immense importance to the team - averaging 186.5 at the Cup, with back-to-back centuries - coupled with the rarity of the breach, means that it is unlikely that such a scenario will occur again, though another incredibly tight clash could keep the over-rate equation firmly in the skipper's mind.
Yesterday's clash was a lengthy game - the West Indies' bowling innings finished nearly 30 minutes behind schedule as well - but the Black Caps' time infringements likely came as a result of their intense discussions and planning at the death when bowling to Carlos Brathwaite.
Williamson wasn't the only Black Cap to take a hit to the wallet yesterday, with every New Zealand player being fined 10 per cent of their match fee for their tardiness.
