Whoever prevails in Staffordshire will set up a Wembley showdown with either Northampton Town or Mansfield Town on May 28.
Match preview
Despite only securing their playoff spot on the final day of the season, there was no doubting that Swindon had all the momentum ahead into the two semi-final ties.
Ben Garner had witnessed his side post four successive wins to secure a top-seven spot, scoring 10 goals and conceding just twice during that quartet of fixtures.
The Robins continued that form in the first leg at the County Ground on Sunday, two goals from Harry McKirdy putting his side in total control of the tie with a quarter of the contest remaining.
However, James Wilson's effort seven minutes from time has the potential to turn the tide in Port Vale's favour, both clubs aware that this has theoretically become a 50-50 tie.
That will be disputed by a Swindon side who have produced the far better form of late at a time when Port Vale have suffered back-to-back home defeats to Bristol Rovers and Newport County respectively.
Nevertheless, Darrell Clarke's team denied Exeter City the League Two title on the final day of the season, and that result has given them the extra belief required to remain on course for promotion.
What Vale will be wary of is Swindon's spectacular away return during the regular campaign, a total of 43 points from 23 outings the best effort by as many as four points.
One of their 13 victories came in the corresponding fixture back in January, Swindon posting a 3-1 victory at Vale Park having been helped by the first-half dismissal of home goalkeeper Lucas Covolan.
Swindon have scored in each of their last seven fixtures in the fourth tier, whereas Vale have conceded seven times in their last three home matches.
Port Vale League Two form:
Swindon Town League Two form:
Team News
Having been left unhappy with the level of his team's performance on Sunday, Clarke will contemplate making changes to his Port Vale XI.
Jamie Proctor appears in line to return in attack in place of Ryan Edmondson, while Jake Taylor is also in contention.
Chris Hussey could make his return at left-back or left wing-back if he has shakes off the injury which kept him out of the first leg.
While alternations will likely be made to the home side's team, Garner may be prepared to stick with his previous Swindon starting lineup.
The more defensive-minded Akinwale Odimayo is an option at right-back with Mandela Egbo potentially dropping down to the substitutes' bench.
Port Vale possible starting lineup:
Stone; Smith, Martin, Hall; Worrall, Pett, Garrity, Gibbons; Charsley; Proctor, Wilson
Swindon Town possible starting lineup:
Ward; Odimayo, Baudry, Conroy, Iandolo; Payne, Reed, Williams; McKirdy, Davison, Barry
We say: Port Vale 1-2 Swindon Town (Swindon to win 4-2 on aggregate)
Back on home territory, Port Vale will fancy their chances of turning things around to earn a spot in the final. However, we cannot ignore Swindon's recent winning streak, a run of results which should provide them with the confidence to move closer to promotion.