England played the first of their two World Cup warm-up friendlies this weekend, beating a decent Nigeria side 2-1 with goals from Gary Cahill and Harry Kane.
The performance faded in the second half after the Super Eagles' clever change of system at the break, but there were signs of encouragement in the first as Gareth Southgate persisted with the back three system used in friendly dates in November and March.
However, with the Three Lions yet to test their new formation in a competitive fixture, several questions remain as to its efficacy.
The fact is that, in five games playing three centre-backs, England have only managed a mere four goals. They twice drew 0-0 to Brazil and Germany late last year, before finding the net only once in games against the Netherlands and Italy.
With Harry Kane restored to the starting XI against Nigeria, the side carried much of more of goal threat this weekend, but still, they relied on a set piece to seal the victory.
#5 Bus-parking opponents
FIFA were seen to have done England a massive favour at December's World Cup draw, with Gareth Southgate's side placed into Group G alongside Belgium, Tunisia and, in their first-ever finals appearance, Panama.
According to most bookmakers, the two European sides will breeze past their minnow opponents in matches one and two before deciding top spot when they meet in Kaliningrad on 28 June.
Any fans who followed the Three Lions in previous tournaments, however, will be much more cautious. In 2010, they were held to a goalless group stage draw by Algeria, four years after labouring to a late 2-0 win over Trinidad and Tobago.
Unlocking deep defensive blocks of the kind Tunisia and, in particular, Panama will likely employ in Russia requires creativity and imagination, something England - by not selecting Jack Wilshere or Adam Lallana - chose to leave out of their final squad.
Against Nigeria, they were able to open the game up by scoring from a set piece in the first seven minutes, but opponents in competitive fixtures more often than not keep it tight in the opening stages. Without an early goal, they may struggle to find their rhythm.
#4 Shaky Stones
One of the most important ingredients in a successful three-man defence system is a composed centre-back capable of stepping into midfield and contributing to the build-up in possession.
In the absence of an experienced alternative, Gareth Southgate has no choice but to entrust this vital role to 24-year-old John Stones, a player who lost his place in the Manchester City side last season following a dramatic dip in form.
While he certainly possesses the required attributes to play the role, Stones' tendency to lose concentration in vital moments has to be a big concern. It's rare that a Three Lions match goes by in which he doesn't gift the ball to an opposing attacker with a careless pass.
In the World Cup, mistakes of this kind will be punished, particularly when and if England reach the knockout stages.
#3 Midfield holes
Often accused of being conservative, England this year appear to be heading to Russia with a remarkably attacking first eleven. All of Raheem Sterling, Jesse Lingard and Dele Alli are predicted to line-up behind Harry Kane, leaving just one player in a deep-lying midfield role.
That means that whoever is appointed to the "number six" role - the leading candidates being Eric Dier and Jordan Henderson - faces an enormous burden of responsibility. Not only do they have to shield the defence, they also have to collect the ball from deep and help launch attacks.
In this regard, Gareth Southgate's side are unique. Most other nations heading to Russia are expected to deploy a double pivot, giving them greater protection for their defences and giving them an extra passing channel in the centre of the park.
While the forwards will undoubtedly be encouraged to drop back in support of their teammates, their attacking instincts will leave gaping holes when their opponents have possession. Teams like Belgium will punish that.
#2 Wasting Dele Alli
Gareth Southgate's system employs only one out-and-out number 10, with two attack-minded midfielders supporting from deeper areas. That means that one of Raheem Sterling and Dele Alli will not be played in their preferred position.
It was Sterling who lined up behind Harry Kane against Nigeria and having netted 23 goals last season for Manchester City, he seems like the natural choice to take the shirt in Russia in two weeks' time.
In consequence, Alli will be left in an unfamiliar role next to Jesse Lingard in midfield. Instead of arriving in the penalty area to latch onto near-post crosses - as he frequently does for Tottenham at club level - he will be chasing balls out on the wing.
The crux of the matter is that England risk wasting one of their three most gifted players in a position to which they are not suited. It's Paul Scholes and Euro 2004 all over again.
#1 Lack of goals
The 23 players Gareth Southgate has selected for England's World Cup squad have so far scored a combined 57 goals wearing the colours of their national team. For context, French duo Antoine Griezmann and Olivier Giroud have 51 between the two of them.
This won't be an issue for the Three Lions if Harry Kane - who is responsible for 13 of them - has the sort of tournament fans expect him to, but should he suffer a dip of form or (heaven forbid) an injury, they could find themselves in trouble.
Despite being prolific at club level, neither Dele Alli nor Raheem Sterling are consistent goal scorers for England. So far, they've only found the net four times between them, and those have largely come against subpar opposition.
From the bench, Southgate can call upon striker duo Jamie Vardy and Marcus Rashford, but there is a still a serious shortage of goal power from other areas of the pitch, particularly the midfield.
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