The possession stats showed that Pompey dominated the ball in their League One home clash with Burton.
But despite a total of 77 per cent in their favour, the hosts were unable to test visiting keeper Ben Garratt enough.
It meant that goals either side of the interval from Mike Fondop and Joe Powell got the job done for the Brewers, with Charlie Daniels’ late header a mere consolation.
And Danny Cowley knows his side need to find a more clinical edge if they want to remain in the play-off spots.
The Blues boss said: “The overriding emotion is frustration because when you concede a soft goal against a team like Burton, you make life difficult for yourself.
“Our play in the first half was good – with control and rhythm – until we got to the final third, where we didn’t have the execution.
“We rushed quite a few decisions and want to try to upgrade our chances against a side that were dropping to a drop six.
“You need to move the ball quickly to get inside of them and give passes for your front players to run onto. We tried to force things a bit.
"Our play in the first half was good – with control and rhythm – until we got to the final third, where we didn’t have the execution."
“We needed more penetration and if you don’t have that, then they’ll just sit in. You might have a lot of possession, but you won’t hurt them.
“It was tough to concede from a free-kick within two minutes of the second half and we made some changes.
“I thought the substitutes sped our play up and meant we showed some real purpose, but we came up short in terms of quality and there’s definitely work for us to do in that area.
“Credit to Burton because they have a clear, direct style and asked us a lot of questions. You can’t criticise that unless you beat it.”
There was more bad news for Pompey, as Lee Brown limped off midway through the first half to join Michael Jacobs in the treatment room.
Cowley said: “It looks like we’ve lost Michael for the season. He had a medial knee injury at the start of the campaign, then got a kick at Wigan and it’s flared up.
“This time it looks like a grade three, which will require an operation, so it’s certainly not ideal. We’re really short at the top end of the pitch.
“Lee’s got a soft tissue hamstring injury. We’ll have to pick the bones out of that and work out why it’s happened.”