England manager Martin Johnson warned his "rusty" team that they face World Cup elimination if they do not improve on their stuttering win over Georgia.
A Dimitri Basilaia try on the brink of half-time capped a strong first half for Georgia and meant England were only 17-10 up at the break.
Johnson admitted some of his players may have lacked match sharpness.
"It wasn't good enough. If we're happy with those standards we'll go home early," he said after the 41-10 win.
England conceded a string of penalties at the breakdown and scrum, with Dylan Hartley sent to the sin-bin just before half-time for using his hands in the ruck.
"The guys need to be a bit more patient and trust our defence," added the World Cup-winning captain.
"Some of it was sloppiness, a bit of rustiness maybe and the guys were a bit over-eager at times, but they have to learn they will be penalised.
"We need to be a bit sharper and we are under no illusions that we need to get better.
"I'm just a bit annoyed. There were lots of chances for us to do better. When we executed simply we made it easy but we just over-complicated it and the higher level you go the simpler it is.
"If ever we needed an understanding about what things are about at this level then watching Ireland v Australia was it - it's a simple game."
Talking about the 14 penalties England conceded, captain Lewis Moody said: "We made it hard for ourselves. We gave away a lot of penalties and made a lot of mistakes at the breakdown.
"Fair play to Georgia, I thought they played a fantastic game. They were physical, as we knew they would be. They've come a long way since we played them in 2003, so credit to them."
England are top of Pool B, above Scotland on points difference. They play Romania on Saturday, before facing the Scots on 1 October.
Georgia coach Richie Dixon believed his team "gained a lot of respect" after their battling performance against the Six Nations champions.
"If we had converted those kicks it would have been a lot closer," said the Scot, who was left to rue the five penalty kicks missed by outside-half Merab Kvirikashvili.
"The contact area is something we have been concentrating on and I think England were surprised by our ferocity."