Barnsley became the latest Championship side to be knocked out of a cup competition by Pompey this season.
Birmingham and QPR have already been accounted for by Kenny Jackett’s men, who are still fighting on three fronts.
Those first two conquests came in the Carabao Cup, while the Tykes were knocked out in the fourth round of the Emirates FA Cup.
Goals from Ben Close, John Marquis, Ronan Curtis and Christian Burgess sealed a comfortable 4-2 victory at Fratton Park.
And Jackett was thrilled with how his Pompey troops fared against their opponents from a higher division.
The Blues boss said: “It was certainly an exciting game and I thought there would be opportunities at both ends of the pitch.
“I’m pleased to say we took more of the chances in what was quite an open contest, with some very good finishing.
“We couldn’t sit off Barnsley as the home side and we were always looking to take the game to the opposition.
"I’m pleased to say we took more of the chances in what was quite an open contest, with some very good finishing."
“I think that it helped for Ronan to miss the Scunthorpe match on Tuesday night because he had a lot of energy, while Ben also looked lively and scored a good opening goal.
“We’re through to the fifth round now and ends a good week for us – we’re looking for our cup runs to continue.
“My thoughts now quickly turn to the league and facing Lincoln on Tuesday, then Sunderland next Saturday.
“But our supporters should be encouraged by the performance and hopefully we can have a really strong finish to the season.
“We’re guaranteed to have at least 59 games – and that’s without going any further in the cups or being in the play-offs.”
Andy Cannon produced an impressive performance on his return to the team, but hobbled off the pitch late on.
Jackett said: “He had a problem with his groin, but we don’t think it’s too bad and he should hopefully be okay for Tuesday.”