Joe Gallen thinks that Portsmouth are growing in confidence after watching an impressive performance secure three points at Sunderland

The Pompey assistant boss looked on as the side made it four wins from five League One matches with a 3-1 win.

Portsmouth took the lead inside seven minutes when Marcus Harness dispatched a finish low inside goalkeeper Lee Burge’s right-hand post after a swift break.

Sunderland levelled within three minutes through Charlie Wyke but Portsmouth reclaimed the lead with 25 minutes gone when John Marquis capitalised on Harness’ through pass.

Portsmouth made sure of the points with five minutes left when Marquis converted a penalty after Luke O’Nien brought down Ryan Williams and was red carded for a second caution.

Gallen said: “It’s a long journey back but it will make it easier! We played very, very well today and our team played very well. It was a great performance, particularly in the first half.

“We took the lead and got back into the lead. The second half will be a bit tougher but, overall, the journey will be a bit quick.

“Away from home, we are scoring goals in the first half. Confidence is building and the formation change has helped us in terms of creating chances and scoring goals.

“We’ve been a bigger threat and the goals have come off the back of that but there are still plenty of games.

“The break was swift for the first goal, with Marcus passing it into the net because he’s a great finisher in there. It feels the formation has given us more potency and we’re building confidence.”

Sunderland manager Phil Parkinson has demanded an immediate improvement from his side ahead of Tuesday’s trip to Rochdale.

Sunderland, who had kept five clean sheets in a row before the visit of Pompey, gifted the visitors the opening two goals by handing them possession in the build up to Harness and Marquis’ goals.

Parkinson said: “We didn’t start the game well enough today, Portsmouth surprised in the way they played. They pressed us, they were physical, we had too many square passes, and we gave the ball away too cheaply. We got punished for that. They pressed us. We need to make better decisions.

“We have done well recently and today we didn’t do it and we got punished. It was a good response after the break, we had a really good period in the game but we needed a goal in that period and we didn’t get one.

“We can’t be flat because we have had a good start. There will be set-backs during the season. This is a knock for us.

“We need to make sure the performance is a good one from minute one until the last minute on Tuesday. We played well for a period of the game here but that isn’t enough to beat one of the teams who will be in the top six.”