First-half goals from Ethan Galbraith and Josh Key proved enough for victory at Fratton Park, with Swansea missing chances to extend their advantage before Jacob Brown pulled a goal back for the hosts in the second period.
But the Swans, who have been in spectacular form on their ground since Matos took charge, held on relatively comfortably to claim only a fifth away win this season.
“I think we had good performances away from home, but we didn’t get the points from the performances,” added Matos.
“We needed to improve a few things to keep winning games away. That’s what we have been trying.
“[At Portsmouth] we got a little bit of both. The mentality was there, the resilience was there, the organisation was there, then of course the performance as well. I am really happy for the team club, for the club and for the fans.”
