Kenny Jackett admitted there was still disappointment among his squad as Pompey reported back for training today.
But he insisted the players need to build on the promise shown on Saturday, regardless of Terell Thomas’ stoppage-time winner for Wimbledon at Kingsmeadow.
The 1-0 defeat sees the Blues occupy 18th position in the League One table going into Tuesday night’s home fixture against Lincoln.
The visit of the Imps is the first of two games in five days, with a Pompey trip to Bristol Rovers on Saturday also in the offing.
Jackett said he understood why morale would be low in the camp as they prepare for a ‘big week’ ahead.
Yet he remained confident his squad had the ability to convert their overall play into wins.
The Blues boss said: 'It's a big week with Lincoln and then Bristol Rovers away.
'Both difficult games, I understand that, but similarly, if we get our game right we do feel they are winnable games as well.
'We have to view it that way.
‘We're obviously disappointed (with Saturday’s result).
‘All of us, the players are disappointed, with the result in a game we controlled for long periods and also created a number of chances.
'We're frustrated because we showed a lot of promise on Saturday, and there was promise.
‘We just couldn't get over the line and convert that into wins and into goals.
'We have to keep delivering on in terms of our product from Saturday, but then whenever we can from those situations be clinical, and as I said, get ourselves over the line really with an edge to our performance.’