But the Blues boss made it clear his team won’t be the real deal in League One until they’ve added consistency to their game.
And Mousinho promised there will be no getting carried away by Pompey’s positive start to the campaign.
Two big performances on the road returned four points in trips to Derby County and Barnsley in the past week.
But the Blues head coach stressed there’s still a long way to go - both in the season and his team’s development.
Mousinho said: ‘Winning games and winning games away from home against good sides is the trait of a promotion contender.
‘And certainly what we did last Saturday, when the chips were down and coming back into the game.
‘Likewise, coming through it when the chips were down at the back end of Tuesday’s game.
‘There were disappointments about how we came through the second half, but we came through with the win after a lot hadn’t gone for us in terms of player availability.
‘That is the sign of a squad which is coming together, I think.
‘But we still have a hell of a long way to go. We’re only eight games in.
‘So we have to make sure we don’t get carried away.’
Lincoln provide the next test for Pompey, as they aim to make it 20 league games unbeaten this weekend.
Backing up the platform they’ve built with a consistent run is Mousinho’s challenge to his players now.
He added: ‘The biggest sign of anyone who wants to achieve anything at any level is consistency.
‘You can’t get carried away with one or two results.
‘That’s the way we’ve been trying to do things this season.
‘On the flip side, when we’ve drawn and not won games we’ve tried not to get too obsessed with anything other than performance.
‘There have been a couple of performances when we felt we needed to do more. The two which spring to mind are Cheltenham and Stevenage.
‘There are other draws where I thought we were excellent, like Bristol Rovers and Derby.
‘There’s always chances to improve and we want to keep the hammer down, but the most important trait is consistency.’