England's much-vaunted attack clicked impressively in their opening World Cup win over Croatia, but defensive fears linger as they attempt to seal a place in the knockouts on Tuesday.
Thomas Tuchel's men were twice pegged back in the first half in Arlington, Texas, before upping their game to win 4-2.
It was an impressive performance against an experienced if ageing Croatia team, but there will be stiffer challenges ahead against sides who boast more pace and firepower, such as France, Spain and Argentina.
Next up for England are Ghana in Boston -- the Three Lions will go through to the last 32 as Group L winners if they beat the African side and Panama fail to beat Croatia.
On the surface, the problem is not obvious. After all, England breezed through qualifying without conceding a single goal in eight matches.
But their defense has two major weaknesses -- a lack of experience and a worrying injury record.
Former England defender Gary Neville, now a Sky Sports pundit, said the team's first-half display against the Croats would have unnerved them.
"I think that it will make Thomas Tuchel adjust for maybe games two and three, and make him think slightly differently about how he sort of maybe plays that defense, and how he looks at protecting them," he said.
The head coach opted to leave three players with significant tournament experience at home -- Real Madrid right-back Trent Alexander-Arnold and Manchester United pair Luke Shaw and Harry Maguire.
England lost Tino Livramento to injury before they had kicked a ball in anger, replacing him with Trevoh Chalobah, who has just one cap under his belt.
- Inexperience -
It means the nine defenders in the 26-man squad have a total of 191 caps between them, with 90 of those belonging to John Stones.
Three members of the back four -- the injury-prone Reece James, Ezri Konsa and 21-year-old Nico O'Reilly -- were making their World Cup debuts against Croatia.
The main debate centers on whether Manchester City defender Marc Guehi should replace Konsa in central defense, though the Villa defender has been a favorite under Tuchel.
The German values the experience and composure of Stones even though he started just five Premier League games last season before leaving City.
But former England striker Chris Sutton believes Tuchel should pair Konsa and Guehi rather than start Stones, whom he says lacks the athleticism of the two younger defenders.
"I think Konsa and Guehi have better attributes in terms of one-against-one situations than John Stones and there will be times in games when they will be isolated one-against-one against players of the highest class," he told the BBC.
England forward Ollie Watkins is less concerned, brushing aside concerns over the back four while speaking to reporters at the team's training base in Kansas City on Sunday.
"I think people are always going to try and criticize and find certain areas they can pick on but I think defensively we've got world-class players at the end of the day who have won major trophies and played at the highest level possible," he said.
"I think maybe we started the game a little bit nervously the other day but you've seen once the nerves are out of the lads' system, I think in the second half we absolutely blew Croatia away."
