The two key mistakes identified as Arsenal punish Portsmouth in FA Cup

That’s according to BT Sport pundits Michael Brown and Martin Keown in their post-match analysis of Monday night’s events at Fratton Park.

Kenny Jackett’s third-placed League One side suffered a 2-0 loss to the Premier League outfit as the Blues’ interest in this year’s Cup came to an end.

Goals from Sokratis Papastathopoulos (45+4 minutes) and Eddie Nketiah (51) proved the difference as the visitors’ top-flight class shone through in the end.

Both efforts could have been avoided, though, in the opinions of former Blues skipper Brown and Keown – who was part of the Gunners’ 2003-04 Invincibles side.

Providing a critical eye, Brown highlighted the acres of space afforded to Reiss Nelson in the build-up to Arsenal’s opener, following a corner.

Meanwhile, Keown believed Pompey’s marking could have been better for the second goal, after the young Gunners winger beat Steve Seddon for pace down the right before delivering the ball into the box.

And the duo were in agreement that such fine margins will always be punished by the Premier League elite.

Brown, who played for the Blues in the 2010 FA Cup final defeat to Chelsea, said: ‘How you set your team up, Kenny Jackett is relentless in what he gives, the amount of information.

‘But on the set-piece, it’s the nearest person that needs to go and press the ball (and Nelson).

‘You can’t blame the staff there.

‘So, who’s taking responsibility on the pitch?

‘Nobody has done it and that just shows you that at this level you can’t afford to do that – or you will be punished.

‘Sometimes you are marking your man and you get run out of an area.

‘But, literally, no-one’s said: ‘where’s Steve Seddon, where is the left-back in this key area?”

‘If he’s in the middle marking, who’s the first person, who’s the nearest one to go – and nobody did that.

‘That gave (Nelson) the room and obviously, they swept the ball home.’

Keown admitted covering Pompey defender James Bolton was unlucky not to clear the danger before Nketiah pounced right on the goal-line to seal the Arsenal win in front of the Fraton End.

However, the former England centre-back believed the forward was able to ‘drift’ into the area between Bolton and fellow defender Christian Burgess.

‘Nelson does exceptionally well (in the build-up),’ said Keown.

‘He travels really well with the ball.

‘You could question the marking in the box, but he (Nketiah) gets in there and then he has the composure when the ball falls to his feet to find the necessary finish.

‘Looking at the central defenders, I think he (Bolton) has been unlucky.

‘He actually gets across, makes the block and the ball sort of stands in time and Nketiah is composed enough to put it away.

‘But I think you’ve got to get a touch, get touch tight whenever the ball is in the box, and he drifts between two central defenders.’