The key ingredient that Portsmouth's formation switch has given them

The change from Kenny Jackett’s previously-favoured 4-2-3-1 has given the Blues the shot in the arm they needed after a stuttering start to the season.

It’s yielded five victories in six matches – including three impressive straight wins over Burton, Sunderland and Northampton.

The Blues are playing more free-flowing football, with centre-midfielder Andy Cannon and right-winger Ryan Williams really benefiting from the tactical tweak.

Gallen feels there’s now a better conduit between the engine room and the front two of John Marquis and Marcus Harness.

The assistant boss said: ‘Having two players up front and four behind that has certainly helped out middle-third football and our ability to pass from the middle third to the final third.

‘Having two players and four behind has clicked. You need to be a little bit flexible. It's suited but who's to say it will suit in other games?

‘You have to look at the opposition a little bit but we are trying to find a way for ourselves and forgetting about the opposition.

‘ The midfield role is being on the ball and off the ball, having both sides of the game and we've done that very well.

‘ The wide players have been able to receive the ball on the half-turn, interchange, play some decent passes and some good football.

‘Having Marcus Harness is very good knitting things together and John is a goalscorer. There's a nice balance at the moment.’