Pompey began the 2021/22 League One campaign by keeping four successive clean sheets.
But there have been just two shut-outs since, including Saturday’s narrow victory over Bolton at Fratton Park.
Danny Cowley was delighted with the resoluteness of his troops in that contest and singled out Connor Ogilvie for particular praise.
Now he wants to see a positive all-round performance when Cheltenham visit the south coast this evening.
The Blues boss said: “Four points from the past two games has been a real positive for us – but it’s something we want to build on.
“We’re certainly pleased with those displays, although we arguably performed better – certainly offensively – at Accrington than on Saturday.
“But I thought that from a defensive standpoint, the Bolton match was the best we’ve been for a number of games.
"Four points from the past two games has been a real positive for us – but it’s something we want to build on."
“Those fundamental principles were there for all to see and football games are always easier to win if you don’t concede.
“Connor’s display was probably the best we’ve seen from him in a Pompey shirt after a stop-start pre-season.
“The quad injury set him back and we started to see what we know he’s capable of. He’s a robust, resilient defender, who also has quality in possession.”
Cheltenham are currently 16th in the standings after securing the League Two title at the end of last season.
Cowley said: “We have a lot of respect for the job Michael Duff has done since the moment he came into the club.
“They got to the play-offs the season before and just missed out, while last term they were best team in that division.
“Already they have picked up a lot of points in League One and they’re a very difficult side to play against.
“Cheltenham are well organised against the ball, while getting a number of balls into the box to provide a goal threat. They ask a lot of questions at both ends of the pitch.”