A spell of fine finishing in a 16-minute period during the second half ensured Pompey would be heading to Wembley.
Their Checkatrade Trophy semi-final at Bury was goalless at the break, but the visitors certainly did some damage once the action restarted.
A fine free-kick from Gareth Evans was followed by strikes from Oli Hawkins and Ronan Curtis to see off the in-form League Two outift.
Kenny Jackett praised Pompey’s opponents for the way they performed, but is excited about leading the side out at the national stadium next month.
The Blues boss said: “Coming to Bury was never going to be easy and it was tough for us during the first half.
“But we adjusted things during the break, got into them and you could feel that the goals were coming.
"It’s excellent to come here and win 3-0. Wembley is something to tuck away now and look forward to."
“We had to stop Bury from playing out because they’re good at it, so we needed to compete a little higher and do things earlier instead of letting them build up steam.
“It was an excellent strike from Gareth and the others followed quickly afterwards, so hopefully we can build on this now.
“It’s excellent to come here and win 3-0. Wembley is something to tuck away now and look forward to.
“The competition has been great for us. We’ve blooded some young players in the earlier rounds which will help us – maybe not this season, but in the future.
“I’m sure there will be some genuine excitement from the fans because Pompey haven’t been to Wembley for a few years.”
Jackett now hopes that the Blues can use the result as a catalyst to improve their league form, with Bradford visiting the south coast on Saturday.
He said: “We’ve had five draws on the spin and that was our first win for a while, so we want to take it into Saturday.
“Hopefully it can kick us on and give us some confidence because we do look like we’ve needed it at times.”
The one blow for Pompey was the sight of Christian Burgess being helped from the pitch in the closing stages.
Jackett said: “He got quite a bad bang on the ankle and had to come off. We’ll have to see and it’s hard to call at the moment because it was quite swollen.”