He performed a key role last season as Pompey secured the League Two title.
But Kal Naismith has had to deal with being a more peripheral figure under Kenny Jackett so far this term.
The attacker has not started a league match since mid-August, although he was given a chance to impress at Charlton in the Checkatrade Trophy.
And Naismith hopes that he did enough in the 1-0 group stage victory to warrant a run in the Blues side.
He said: “It’s not been nice, but there are guys all over the country who aren’t getting games and it’s the same for them.
“I haven’t been playing much recently, but I’m at Portsmouth Football Club and am thankful for that every single day.
"It’s a tough job for the gaffer because there’s a squad of 25 players and everyone wants their chance."
“Of course it gets frustrating when you’re not in the team, although I’ll never throw in the towel.
“I see some messages from fans and it’s nice that they know what I can do, so now I want to be able to prove that.
“It’s a tough job for the gaffer because there’s a squad of 25 players and everyone wants their chance.
“I don’t feel I’ve got mine yet for whatever reason, but will just keep working hard and can hopefully get a run of games.”
Naismith provided the assist for Curtis Main’s winning goal at The Valley, which secured Pompey’s progress to the knockout stages.
He said: “We had a lot of possession and we needed to get that feeling of winning back again.
“To be able to celebrate – no matter what the competition is – was a positive thing because a side like Pompey can’t be losing five games in a row.
“I just had to stretch to get the ball back across goal for Curtis to come in and do what he does best. He’s got that instinct to be in the right place.”