Pompey had looked to be cruising at 2-0 up in their Emirates FA Cup clash with Barnsley at Fratton Park.
But Cauley Woodrow’s stunning strike on the hour mark got the Championship side believing a comeback was on the cards.
Ronan Curtis had other ideas, though, finding the net off the inside of the post following a long clearance up the pitch by Alex Bass.
The hosts went on to complete a 4-2 victory and the Republic of Ireland winger was delighted with their display.
He said: “You’re always wanting to test your ability and I thought it was a deserved result against Championship opposition.
“We knew what Barnsley were capable of, but were able to match them and it was good to go in two up at half-time.
"Everyone was buzzing in the changing room after the game and we want to get a really big side in the next round."
“It was important that we didn’t let the tempo drop after that because it was always going to be a tough battle.
“They had just got one back and then had a great chance to score again, but we went straight down the other end.
“Bassy got the assist and it was a great kick from him. I just gambled really and was able to get my body in front of the defender before sticking it in the net.
“We kicked on from there and got another goal to secure the win. We’re delighted to be in the fifth round.
“We’re always trying to do our best in every game – for the fans and for the manager. We just give our all and have produced in recent weeks.
“Everyone was buzzing in the changing room after the game and we want to get a really big side in the next round.”