Six Nations: Martin Johnson relief at tough England win
Johnson frustrated with disjointed win
Martin Johnson admitted England were "never comfortable" as they beat Scotland to move within one victory of a first Grand Slam for eight years.
"We were clearly a little bit off it. They knocked us out of our stride a bit," the England boss told BBC Sport after the 22-16 win at Twickenham.
"It felt like the longest game of all time and it was always tough."
England captain Mike Tindall added: "We're not happy with the way we played, especially in the first half."
But the Gloucester centre, who went off at half-time after injuring his ankle, added: "You've got to give a lot of credit to Scotland, they took us on.
"It's good to see when you're not playing that well you can still get those wins. I think the Grand Slam still won't be allowed to be discussed, it's still another game."
England travel to Dublin on Saturday to face Ireland in their final game and victory would give them a first Grand Slam since 2003.
If they avoid defeat, they are guaranteed to win the Six Nations title but even if they lose, they look likely to top the table.
Wales, the only side who could deny England, must beat France convincingly in Paris in their final game and hope England lose heavily, with Johnson's side enjoying a vastly superior points difference of 42 (+67 to Wales' +25).
England have been in far better form this season after a difficult couple of years under Johnson, but they struggled to put away a Scotland side who are anchored to the foot of the Six Nations table.
Tindall unhappy despite win
"We had too many turnovers in the first half and the second half was a strange one, with a big injury [Scotland flanker Kelly Brown was stretchered off after a lengthy delay], then the referee [Romain Poite] getting injured - it got a bit disjointed," said Johnson.
"It was [the kind of] game we knew could happen if we didn't get it right often enough, and we didn't get it right often enough.
"We created enough chances, but we were turned over far too often, some of it was their good play and some of it was us being a bit too optimistic at times.
"Not being able to finish it off in the second half really hurt us. The game is about the fundamentals and we didn't get the fundamentals right often enough under that pressure."
England flanker James Haskell, who won the man-of-the-match award after a powerful display in attack and defence, said it was "one of the toughest games I've ever played in".
He added: "The team dug in and showed a lot of character. We'll take the win but we've got a lot of work to do."
Despite the defeat, Scotland boss Andy Robinson was extremely happy with the way his side had performed.
"I've just said to the players that I'm delighted with the way they've gone out and tried to play, but we've got to be more efficient at the set-piece if we want to challenge the very best," he said.
"When you see a performance like today - the way we defended, and the Max Evans try was a cracker, we were able to keep ball in the opposition 22 and we were able to ask questions of them but it's a ruthless old game this.
"They played well today. Their counter-attack was good, and when they put pace onto the ball they played with good shape.
"We targeted the breakdown as an area we could get turnovers and thought we did well in that area.
"If our line-out was better and we hadn't given scrum penalties away, we think we would have won the game."
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