Gareth Southgate said he understands supporters booing England off after losing Friday's friendly to Iceland but vowed his team will be ready to fire at Euro 2024.
The Three Lions lost their final warm-up game 1-0 as Jon Dagur Thorsteinsson's 12th-minute strike was enough to give the visitors a famous win at Wembley.
Many of the 81,410-strong crowd opted to boo England at half-time and full-time of a game in which Harry Kane and Phil Foden wasted excellent opportunities but they managed just one shot on target, their fewest in a game since June 2021.
Asked about the negative fan reaction, Southgate said: "Completely understand -- we didn't play well enough to keep them excited within the game.
"We had some very, very good chances which normally would be finished which could have given a different complexion to the game and affected the confidence of the opponent. But that might also have masked some flaws that were apparent tonight.
"From my perspective, I've learned a lot from the game but no qualms with the supporters' reaction.
"To have the fans with you here obviously makes a massive difference but you have to give them enough goalmouth action, you have to play well enough, press and win the ball with intensity to keep them with you during the game and tonight we didn't do that so we have to accept the reaction as it was."
England face Serbia in their opening Group C match against Serbia on June 16.
"We'll be ready," Southgate said. "Tonight hasn't gone as we would have hoped. I said to the players that not every day will go as you want and tonight was one of those.
"But also not everything will be wrong, we had enough chances really to win the game but we conceded too many chances as well."
John Stones appeared to suffer an ankle problem in the opening minutes of the game and was substituted at half-time for Ezri Konsa after receiving treatment but Southgate played down fears of an injury scare with England set to fly out to Germany on Monday.
"We think he's probably OK but we didn't want to take a chance with that given what's coming up," he added.
Southgate also had no concerns over Marc Guehi, who suffered a head injury in the second half.