Two late goals from Anthony Forde and Tom Bradshaw gave Walsall the advantage over Preston in the Football League Trophy northern area final first leg.
The hosts almost took the lead in the first half but Jermaine Beckford's header was kept out after a diving save from Saddlers keeper Richard O'Donnell.
Forde broke the deadlock on 84 minutes with a powerful free-kick.
And Bradshaw doubled their lead when he latched on to a poor passback from Scott Wiseman and slotted home.
Walsall, who sit 10 spots below third-place Preston in League One, are now a step closer to their first ever Wembley final.
If they hold on to their advantage in the return leg at the Banks's Stadium next month, they will face either Bristol City or Gillingham in the competition final on 22 March.
It was promotion-chasing Preston who looked the most likely to score in the first half, but the Saddlers had O'Donnell to thank for keeping the Lilywhites at bay.
Paul Gallagher's cross was met by Beckford inside the six-yard box, but O'Donnell produced a phenomenal stop to somehow deny his downward header.
Chris Humphrey then blazed over and Beckford again forced O'Donnell into a save, before the visitors responded with Andy Taylor's free-kick which came back off a post.
The Saddlers shaded the second period and they were rewarded with two strikes in six minutes.
Forde hit a 25-yard free-kick into the far corner of the net and then Bradshaw capitalised on Wiseman's error and placed the ball through Thorsten Stuckmann's legs.
- 7HumphreySubstituted forEbanks-Blakeat 74'minutes
- 8KilkennyBooked at 84mins
- 10BeckfordSubstituted forKingat 74'minutes
- 9DaviesSubstituted forReidat 63'minutes
- 4O'ConnorBooked at 66mins
- 9BradshawSubstituted forGrimesat 90'minutes
- 21CookSubstituted forBaxendaleat 78'minutes
- Simon Hooper
- Shots on Target