England struggled with the conditions and their own poor decision-making in the first 50 minutes of the game but scored four tries for what was, on the scoreboard at least, a comprehensive win.

"We showed glimpses of how good our attack can be, we will continue to work on it and we are getting better every day. Later in the competition we will hopefully be firing on all cylinders," Lawes told reporters.

He profited from a large slice of good fortune to score a crucial second try for England with the game evenly poised at 13-12.

The ball ricocheted backwards off the arm of prop Joe Marler and onto the latter’s head, landing perfectly for Lawes to score unopposed as Japan’s players stopped in expectation of the whistle.

"It was a lucky try, but I will take them however they come," Lawes said. "In these conditions it is difficult. I saw it ricochet off (Marler’s) head and thought I should score it just in case (it was not a knock-on).

"It was tough, even when you have a good grasp of (the ball) you go into contact and it can spin out of your hands. It is just so greasy, it is hot and humid and you are sweaty. It makes it very difficult."

Coach Steve Borthwick echoed those views and said it was changing the way teams play in these conditions.

"The players found a way to win, but in these conditions it is challenging," he said. "Japan kicked the ball 37 times, when have you ever seen a Japan team do that? It tells you a lot."

Borthwick said England would get sharper as the tournament progresses after looking aimless at times when they had possession in the Japan half.

"You can see growth in our attack. It always takes the longest to come together because it takes cohesion. We have had three or four months with our full coaching team to work on it, some teams have had eight years."

England play their next Pool D game against Chile in Lille on Saturday.