The Blues have won just once away from home this season, that victory coming at QPR in October.
Picking up points away from Fratton Park is something Mousinho admitted his side have to start doing more.
However, their home record has been much more encouraging, with two of their three victories coming in December when they impressively beat Bristol City 3-0 and Coventry City 4-1.
“If you take the Derby game (4-0 defeat) away from it then the performances home and away in recent weeks have been really positive,” Mousinho said.
“We had a really good away performance at Watford. Of course, you have to take the winning goal into account and make sure we deal with that situation a bit better but by and large I was very pleased with what I saw.
“We have put ourselves in a much better position over the last few weeks. There’s not quite as big of a buffer between us and the relegation zone as we’d like and we have to build on that.
“In a season like this for us you are defined by your home form and that took us a while to get going, but now we are really confident going into these home matches. However, we do need to start picking up points away.”
Portsmouth are next in action on Sunday when they travel to take on Bristol City at Ashton Gate.
