Substitute Thomas Waddingham came off the bench to claim a fortuitous late winner in a game of freak goals at a blustery Fratton Park.

Mousinho, whose team have now taken 10 points from their last four games, said: “I’m delighted with the three points, but my overriding feeling is this is the first time this season we’ve got away with one.

“I don’t think we deserved it on the balance of play, but on the effort and work-rate of the lads to go again, again and again through a difficult schedule we did.

“We were lucky to nick the win off a poor start to the second half and the defending in the first half.

“I felt it was inevitable that in one of these games across this run we wouldn’t be at our fluid best, but we stuck in it and did everything else really well.

“On the level of performance and some of the chances we didn’t deserve to win the game, but in terms of having that bit of luck, the work-rate and ability to stick in games I felt we deserved one of those to go our way.”

Millwall made the brighter start with Jenson Metcalfe scoring the game’s opening goal after six minutes.

Metcalfe capitalised on a calamitous pass forward from Pompey goalkeeper Nicolas Schmid before slotting home.

A response came 10 minutes later when Adrian Segecic’s scuffed free-kick deceived Lyndon Dykes at the near post, forcing the Millwall forward to turn the ball into his own net and make it 1-1.

Waddingham secured the points for in-form Pompey eight minutes from time in comedy fashion.

Millwall captain Jake Cooper saw his attempted clearance inside the box ricochet off Waddingham and into the back of the net.

Millwall boss Alex Neil felt his team shot themselves in the foot.

Neil said: “I thought we were relatively comfortable, but some of the mistakes, errors and naivety have meant we have managed to lose the game.

“For large spells we are arguably the better team.

“The first goal we conceded was really poor and we did not deal with a cross into the penalty area. After that we went a bit passive for the next five minutes for some reason.

“The game became a little bit stretched and we made some very naive errors, especially with the second goal. We started kicking the ball off our own players and it just looks messy from our point of view.

“The conditions were not helpful but that was the same for both teams so that’s not why we lost.”