Pompey are searching for the spark that would reignite their League One promotion hopes.
A run of four defeats from the past seven games has stretched the gap to the top two to seven points.
The Blues now also have to be extra wary of the chasing pack sitting just outside of the play-off positions.
And Joe Gallen wants to see his side find a clinical edge when they travel to in-form Oxford on Tuesday evening.
Pompey’s assistant manager said: “We’ve played them a lot over the past few years – including the play-offs – and it’s always been tight.
“They know a lot about us and we know a lot about them, but we’re looking to put things right off the back of two defeats.
“Our passing and play in the middle third has been pretty good. We put a lot of balls into the box on Saturday, but were unable to come up with the finish.
"We’re remaining positive in our outlook, but have to start picking up points again."
“So in terms of creating chances, we’re expecting a much better performance. Hopefully we can take some of them and score goals.
“There are 18 games to go and it’s not quite the run-in yet. We’re remaining positive in our outlook, but have to start picking up points again.
“We’ve got a strong squad and all the players always want be involved and I’m sure there will be an opportunity for some of them at Oxford.”
Michael Jacobs will not be involved, however, as he continues to progress in his recovery from a hamstring problem.
Gallen said: “Hopefully he will be back in training on Thursday, although Saturday’s game would be too soon for him.
“Considering it’s a hamstring injury, you need at least a full week of work before being up for selection again.
“He has produced some good performances and we’re waiting for him to come back and offer us a bit more flexibility.
“James Bolton rolled his ankle in training on Friday and so he’s still out, while Alex Bass also needs a bit of time.”