Eddie Jones believes England's loss to Argentina was partly down to being too focused on next year's Rugby World Cup as he accepted full responsibility for the defeat.
England were on the end of a surprise 30-29 reverse at a packed Twickenham on Sunday – only their second ever home defeat to Argentina.
The sides will meet again in their opening match of the 2023 World Cup next September, which Jones already had one eye on heading into last weekend's battle in London.
"When your team doesn't play to the potential you want, there is always something in the message that you're giving the team that's not quite clear," he said.
"We've been looking at a number of long-term strategies to get ourselves set for the World Cup. Maybe our focus wasn't tight enough on the Argentina game.
"Maybe we were over-thinking a bit, and that's entirely my fault."
England reached the final in 2019 and are among the favourites to lift the trophy next year, alongside New Zealand, Ireland, hosts France and reigning champions South Africa.
The Red Rose endured another disappointing Six Nations campaign earlier this year, but they recovered with a battling 2-1 series win in Australia prior to losing to Argentina.
With less than a year to go before the World Cup begins, Jones is hoping to further develop his squad in time for the tournament.
"There are a cluster of teams at the top of world rugby," he said. "We want to break that cluster. To do that we have to have a number of different ways to play the game.
"This next 11 months is to get enough equipment in our armoury to play any way.
"England rugby is traditionally about power rugby, winning the set-piece, smashing down the gain-line, but we have to learn from the 2019 Rugby World Cup.
"In the final, we came up against a side that had more power than us, and we were unable to beat them at that game."
England have made three changes to their 36-man squad for Saturday's showdown with Japan at Twickenham, which is followed by Tests against New Zealand and South Africa.