When Pompey reached the League One summit at Christmas, they were clinical in attack and stingy at the other end.
And Ben Close knows they need to rediscover that form if a League One play-off spot is to be salvaged.
The Blues dropped to eighth after a 3-1 defeat to Swindon, stretching the winless run to four matches.
But Close believes that with four fixtures remaining, they can still turn things around to finish inside the top six.
The midfielder said: “Frustration is the main feeling for us. We’re not giving ourselves a chance because we’re conceding and having to score at least twice to win games.
“We gave away some really sloppy ones and that’s not like us. We’ve got to get back to being solid again, which is a collective thing.
“But, on the opposite side, we’re also not getting enough goals at the moment to be able to ship one in.
"We obviously need to do better at both ends of the pitch and have to keep working hard to ensure that happens."
“There were times when we got into their box and produced good deliveries, but couldn’t get on the end of things.
“So we obviously need to do better at both ends of the pitch and have to keep working hard to ensure that happens.
“Football can easily turn and once you’re on the back of a few bad results, it feels incredibly hard to win.
“Every team goes through these runs – and we certainly have before – and it’s about our mentality and attitude.
“The lads are obviously disappointed, but we have to put it behind us to make sure we win the next one. You can’t feel sorry for yourself.”
Close returned to the Pompey engine room after missing Saturday’s trip to MK Dons with a groin injury.
He said: “Going from not playing much this season to quite a busy schedule has taken its toll and I just needed those extra few days, but it’s cleared up now.”