Twickenham - England coach Eddie Jones urged officials to make clear what constitutes a head-high tackle ahead of the upcoming Rugby World Cup following his side's 33-19 warm-up win over Wales on Sunday.
Jones felt there were at least two incidents during the game which could have led to a red card, although the Australian refused to be more specific with his thinly-veiled criticism of French referee Mathieu Raynal.
But following the red card handed out to New Zealand's Scott Barrett for a head-high shoulder charge on Australia captain Michael Hooper during the All Blacks' shock 47-26 loss in Perth on Saturday - a decision made by Jerome Garces, another French referee - Jones said World Rugby needed to clarify the position ahead of the World Cup in Japan, which starts next month.
"I thought there was an issue with the referee," Jones, who names his World Cup squad on Monday, told reporters.
"We saw a red card yesterday (Saturday) which affected the game.
"We need to get some consistency into that area of the game.
"In the World Cup if you lose a player through a red card as New Zealand did yesterday, it makes the game very difficult.
"I thought we saw two instances today where that could have happened. I urge World Rugby, although I don't think they do anything at great pace do they, to get some consistency in that area because otherwise we will have games being destroyed by an inconsistent official making a decision on a law that's not clear," the former Australia and Japan coach added.
Jones is not alone in being concerned, with Wales great Jonathan Davies tweeting earlier on Sunday: "Referee will decide who wins the RWC (Rugby World Cup) this year, not the best team unfortunately."
World Rugby are trying to crack down on challenges that could lead to serious head injuries.
But Jones was scathing about the decision to send Barrett off, saying: "I thought it was ridiculous. A bloke gets tackled, he goes to be second man in and his shoulder hits his head and he gets a red card.
"We can't have that in the game. There has to be some common sense applied, but maybe common sense was applied today really well.
England's victory prevented Six Nations champions Wales from going top of the world rankings and also ended the visitors' 14-match winning streak.
It was achieved with anything but a first-choice side, Jones having to make three injury-enforced changes to his original team.
But three first-half tries from Billy Vunipola, Joe Cokanasiga and Luke Cowan-Dickie, all converted by flyhalf George Ford, who also kicked three second-half penalties, and a late Elliot Daly drop-goal saw England to an ultimately comfortable win in the first of four warm-up fixtures
"We learnt a bit about ourselves, learnt a bit about the squad so it was useful," said Jones, whose side again play Wales - a potential World Cup quarter-final opponent - in Cardiff next weekend.
England were also able to withstand a fightback that saw Wales close to within five points midway through the second half.
It was in marked contrast to their previous match, when England squandered a 31-0 lead in a remarkable 38-38 draw with Scotland at Twickenham in March.
"It means we've learnt a little bit from the Six Nations where we let ourselves down a little bit in that area, so that was pleasing for us," said Jones.