England boss Gareth Southgate warned his players that their World Cup progress in Qatar will be curtailed early unless they cut out the sloppiness that crept in towards the end of Monday's superb win against Iran.

The Three Lions roared to a memorable 6-2 victory over Carlos Queiroz's normally obdurate opponents in Monday's Group B opener at the Khalifa International Stadium.

Brilliant Bukayo Saka struck a brace on a night when Jude Bellingham, Raheem Sterling, Marcus Rashford and Jack Grealish also found the net as England ran amok in Al Rayyan.

Southgate praised his players after a win that also came with a warning ahead of Friday's match against the United States as Mehdi Taremi scored two consolation goals.

"We're really pleased to start the tournament in this way and really pleased with our attacking play," he said after Taremi's stoppage-time penalty prevented England from matching their record World Cup win.

"We know that Iran are usually very difficult to score goals against, so it's a credit to our players - their movement, the quality of their passing, the quality of our finishing.

"I didn't like the end of the game. To concede two goals the way we did isn't the level that we need.

"So we're going to have to be better than we were today in certain aspects of our game against the USA because they're going to be coming for us full throttle, and we're going to have to reset.

"I don't like games that drift as this one did and it was difficult because there was so much added time in both halves, so I understand the focus drifting a little, but that won't be enough for us to progress in the tournament.

"So we've still got a lot to do to qualify, but of course it's really, really good start for us."

England take on neighbours Wales after facing the USA on Friday, a match Southgate expects skipper Harry Kane to be available for.

England fans had hearts in mouths early in the second half when the 29-year-old gripped his right foot in pain after being caught by a desperate Morteza Pouraliganji challenge.

"I think Harry's fine," Southgate said of Kane, who reportedly left the ground with a slight limp and his right ankle lightly strapped.

"It obviously looked a bad tackle but he carried on in the game and we took him off, really, because we felt it was a moment we could do that."

Another concern was defender Harry Maguire, who left the field looking groggy after a positive performance.

"He felt ill," Southgate said of the Manchester United captain. "He'd sort of flagged it just before the goal. Given the state of the game we felt no point carrying on. So, other than that, I haven't really seen anything of concern.

"It was nice we were able to refresh the forward the line - not only to get the players off, but to get the other boys on, because there's some really close calls as to who starts in those positions.

"We've got some fabulous talent. We knew we had players that if we needed to change the game could come into the game and have an impact.

"So on days like that you'd like to be able to change more, because every time you pick a team you've got 11 who are happy and, with the size of the squads now, 15 who could react differently.

"But I have to say the reaction when I named the team, when we were working with the team, has been excellent.

"They've competed with each other, but they've supported each other and we've got to continue that now.

"We work with a group of players who have a hunger to play, they're a pleasure to work with.

"They have humility, but they also think about this and it's unusual to have a group like we've got.

"They've been excellent all week. We weren't surprised that they played well today, because the whole squad have been really good from the moment we met."