SOFIA • While there is little need to overreact to England's first tournament qualifying defeat in 10 years, the uncertainty over their best formation has given manager Gareth Southgate plenty to ponder ahead of today's Euro 2020 qualifier against Bulgaria.
Top of Group A with a far superior goal difference despite the 2-1 away loss to the Czechs, the Three Lions remain the odds-on favourites to reach the Finals - an away win coupled with third-placed Kosovo failing to beat Montenegro at home will ensure qualification.
However, Southgate has to look ahead and he knows that it could come down to resolving tactical flaws if England are to make an impact in the Finals.
During England's World Cup campaign last year, he deployed a 3-5-2 system to great acclaim as his team conceded just four goals en route to the semi-finals in Russia.
He has, however, since turned to 4-3-3, partly to accommodate their attacking talent. But he overloaded their offence by starting Raheem Sterling, Harry Kane, Jadon Sancho and Mason Mount against the Czechs and there was an obvious lack of a midfield link in Prague.
Declan Rice and Jordan Henderson were left isolated, with former Manchester United skipper Roy Keane pointing out "they're having no impact on the game".
Former Crystal Palace midfielder Shaun Derry also told talkSport that Southgate "got our lines completely wrong, from the defensive lines into the midfielders".
That flat showing may mean Southgate could return to a three-man defence for the clash in Sofia.
"We are in a difficult situation in terms of the players that have played international football with us in that area of the pitch and who are playing regularly with their clubs," he said.
"It's certainly something we've considered and I don't think we can dismiss. I'm not sure, ahead of Monday, if that's the right thing to do."
With just two competitive games left after their trip to Bulgaria, time is running out for Southgate to find a formula that could bring about their maiden Euros triumph and he also hinted he may even revert to his World Cup formation.
"Players take in tactical concepts very quickly, especially top players," he said. "We have to keep reflecting on what's working, what's possible and learn from every experience we have.
"We'll learn a lot from Prague. We've had straightforward qualifying games that haven't challenged us, but this was a proper test and we didn't come through, so it would be naive not to take the lessons from what we've seen."
REUTERS, THE GUARDIAN