Michael Jacobs came off the bench to make his debut in Pompey’s goalless draw at Rochdale.
The new arrival is working his way up to full match fitness after leaving Wigan at the end of last season.
But the attacking midfielder knows that he has to make a quick impact in order to prove his worth to the side.
And Jacobs enjoyed the opportunity to get his first taste of action in a Blues shirt at Spotland after signing at the start of the week.
He said: “Thursday night probably came a little bit too soon for me after I signed here on the Monday.
“I needed to get a good few days of training into me after having to keep fit by myself at home – there’s nothing like working with other players.
"When you do come on, it’s important to make a difference – especially in the sort of position that I play in."
“It was nice to get out there on the pitch again and, in a cut-throat environment, you need to show what you can do.
“When you do come on, it’s important to make a difference – especially in the sort of position that I play in.
“For me, it’s all about building up the minutes and trying to get my fitness up to the levels that are required.
“It’s been a hectic week with everything that’s gone on and hopefully I can play at Fratton Park next Saturday.”
Pompey had numerous opportunities to turn one point into all three at Spotland, but could not find a breakthrough.
Jacobs said: “We created enough chances to win the game in the second half, but when the ball’s not going in at one end, it’s important to keep a clean sheet at the other.
“It’s a point on the road and if we get a win against Wigan at home next weekend, then suddenly we’re in a good position.
“We’re obviously disappointed not to win the game, but we can’t get too down and have to try to build on the result.
“It’s a long season and you could look back on these first two games as the catalyst that was needed to get us where we need to be.”