Martin Johnson hailed the impact of scrum guru Graham Rowntree after England managed to claim a 16-12 victory over Scotland on Saturday.
The 2003 winners were made to sweat and were behind for most of the game after Chris Paterson and Dan Parks pushed the Scots 3-12 ahead.
But with four points secured, England move on as Pool B winners and will tackle France in the quarter-finals at this same venue a week today.
England were far from impressive though against the hungry opposition, with Johnson praising the half-time turnaround notably in the scrum battle.
“I wouldn’t say we were clinical,” he explained.
“Graham did a great job with the guys at half-time and they came out did a lot better job in the second. We put the try away very well at the end but I wouldn’t we were clinical, far from it.
Looking ahead to their last-eight clash with les Bleus, Johnson stressed that his side needed to up their performance the next time they take to the field in New Zealand.
“We have got to make it easier for ourselves as we go onto the quarter-final,” he added, saying that out-of-sorts fly-half Jonny Wilkinson has a bruised forearm and inside centre Mike Tindall is struggling with a dead leg after the physical game.
“I think the main thing to take from this is our character shown getting out of this pretty tough hole. We’ve seen what this tournament is about in the past and whoever scored the first try today was probably going to get over the line and that is how it turned out. The guys who came on did very well and we handled the substitutes pretty well and got the reward from it.”
By Adam Kyriacou at Eden Park