Eddie Jones admitted England were under-prepared after they began their RBS Six Nations title defence by scraping past France.
The stuttering hosts made hard work of victory at Twickenham, eventually prevailing 19-16 thanks to a first international try from replacement Ben Te'o 11 minutes from the end.
"It doesn't get much uglier than that," head coach Jones told ITV. "We weren't our usual urgent selves and maybe I've got to look at the preparation I gave the team, the preparation wasn't good enough.
"But second half I thought we did enough good things to win the game.
"The attitude of the players has been first class but sometimes these things happen, it's a game of rugby, you've got human beings involved. They (France) played quite well and it took us a long time to respond.
"We made some silly handling errors, just a lack of real urgency to do what we want to do, we're a 'go get 'em' team and we tended to sit back a bit today but we were much better after that.
"It's still ugly but the result's beautiful."
England have now won 15 successive matches since the appointment of Jones.
Captain Dylan Hartley agreed with his coach's view of the performance but praised his side's replacements.
"Plenty to work on, we got through that one," Hartley said. "I think a huge amount of credit needs to go to our finishers today.
"Ben Te'o and James Haskell came on and gave us a good bit going forward at the end there so unbelievable impact from our subs.
"We dug in, we found a way and we'll take something from that. But, look, week one of the tournament, we will take that win but there's plenty to work on.
"We need to be a bit more clinical with the ball in hand and probably not so passive in defence."