Neil Critchley’s men booked a place at Wembley following a 6-3 aggregate victory over Oxford United.
Oxford wrestled the last play-off spot off Pompey on the final day of the season, securing the vacant sixth place.
However, they were unable to overcome Blackpool, who are now 90 minutes away from a Championship return.
Last night’s Bloomfield Road match finished 3-3 - yet the Seasiders had already established a 3-0 first-leg success.
For Karl Robinson’s side, their tough task was effectively over when they slumped to a 5-1 deficit after just 13 minutes of the second leg.
And while the fixture finished 3-3, it’s Blackpool who will fight for a Championship place in the May 30 final.
The Seasiders completed the double over Pompey this season, winning both fixtures 1-0, and finished third in the League One table.
They will now play the winners of this afternoon’s encounter between Sunderland and Lincoln (3.30pm).
Michael Appleton’s Imps are the favourites to go through as they head to the Stadium of Light with a 2-0 first-leg advantage.
Tom Hopper and Brennan Johnson netted second-half goals for Lincoln in Wednesday’s clash to put them in the driving seat.
Sunderland have ended the season unconvincingly, with one win from their last 10 matches in all competitions.
A message from the Editor, Mark Waldron
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