Billed the 'richest game in football', one of these sides will end the bank holiday weekend as a Premier League club as the English domestic season comes to a close.
Villa supporters do not need telling about the gut-wrenching feeling of narrowly missing out on a place in the top tier, having tasted defeat to Fulham in last season's playoff final.
Tom Cairney broke the Villans' hearts 12 months ago and the dream looked to be over for another year following an underwhelming first half to the 2018-19 campaign.
Villa were down in 11th place after snatching a 1-1 draw at Stoke City on February 23, eight points adrift of Bristol City in the final playoff spot.
One point from the last six on offer was not the best way for Villa to build momentum heading into their playoff semi-final with West Bromwich Albion, but it did not matter as they came out on top in an entertaining battle with their West Midlands rivals.
West Brom led 1-0 in the first leg at Villa Park, only for Conor Hourihane to score a superb long-range strike, followed up by a penalty from Tammy Abraham. A Craig Dawson header in the second leg set up extra time and penalties, which Smith's side edged 4-3.
Smith deserves a lot of credit for the work he has achieved during his seven months at Villa Park, having instilled a real collective belief and given supporters reason to be positive once again.
However, much like 12 months ago against Fulham, there is a real sense that this could be boom or bust for Villa in terms of the financial aspect. Losing Jack Grealish, for example, seems certain if they fall just short for the second year running.
It could be argued that Villa are a stronger side this time around, though, and Derby - for all their strengths - are not as good a side as Fulham were heading into the 2018 final.
Taking that loss to the Cottagers into account, Villa have lost five of their last six matches at Wembley, with their only victory during that run coming in April 2015 against Liverpool in the FA Cup semi-finals. They head into this game as favourites, though - a tag Smith needs to ensure his players live up to.
Recent form in Championship (including playoffs): WWDLWW
Whereas Villa have only spent three years outside of the Premier League, for Derby the wait is a little longer. Not since 2008, when going down with a record low tally, have they graced the top flight.
The less said about that campaign the better, though the good times appear to have returned under Frank Lampard, who has been linked with the Chelsea job thanks to his impressive work at Pride Park.
In his first managerial role, Lampard has guided the Rams into the playoffs, doing so thanks to a strong end to the regular campaign.
County took 14 points from the last 18 on offer to finish sixth, matching their league position from 12 months ago when losing to Villa's conquerors Fulham in the playoff semis.
The emotions could not have been any different this time around, though, as Derby became the first side to lose the first leg of a semi-final on home soil and progress through.
Lampard's men lost 1-0 to Leeds United at Pride Park and conceded 24 minutes into the second leg to find themselves two goals down on aggregate.
Bringing on Jack Marriott from the bench late in the first half proved to be an inspired change for Lampard, however, as the striker scored twice in an incredible 4-2 win for the Rams at Elland Road, seeing them through 4-3 on aggregate.
That match may have been emotionally draining from Derby's perspective, but they will have a 12-day rest between games and, in terms of momentum, they are the side in form.
Derby are participating in their fourth second-tier playoff final, losing two (in 1994 and 2014) and winning one (2007) of their previous three.
The Rams finished two points worse off than Villa, meanwhile, and the team finishing sixth in the Championship have been promoted via the playoffs in just one of the last 13 seasons, with Blackpool beating Cardiff City in the 2010 final.
That is not the best omen, though Derby have already created history in this season's playoffs and Lampard now has his sights set on a dream promotion to the Premier League.
Recent form in Championship (including playoffs): WWDWLW
Axel Tuanzebe limped off during extra time of the meeting with West Brom, but the on-loan Manchester United defender is fit and available for selection.
Chelsea loanee Abraham has scored four Championship goals against Derby County - he has only netted more against Nottingham Forest (five).
Derby have a couple of fitness issues to contend with, meanwhile, as Martyn Waghorn injured his Achilles on the final day of the regular season and missed both legs of the semi-final win over Leeds.
Marriott's star showing from the bench at Elland Road last week will likely be enough to earn him a start up top, and there will also be a change at left-back as Ashley Cole is certain to come in for the suspended Scott Malone.
Harry Wilson has been involved in eight goals in his last 10 Championship matches for Derby and has scored 16 league goals this season overall - seven more than any other Rams player.
Aston Villa possible starting lineup:
Steer; Elmohamady, Tuanzebe, Mings, Taylor; Adomah, McGinn, Hourihane, Grealish, El Ghazi; Abraham
Derby County possible starting lineup:
Roos; Bogle, Keogh, Tomori, Cole; Johnson, Holmes; Wilson, Mount, Lawrence; Marriott
Head To Head
The Villans have won six of their last nine matches against their Midlands rivals, all in league competition, losing just once during that sequence - a 2-0 defeat in December 2017.
This is only the sixth second-tier playoff final between the teams finishing fifth and sixth in the division that season and the first since 2005, when West Ham United won 1-0 against Preston North End.
We say: Aston Villa 1-0 Derby County
Villa are the first side to reach back-to-back Championship playoff finals since West Ham in 2005 and they will be desperate to avenge their loss to Fulham almost 12 months ago to the day.
Derby accrued 72 points across their 46 league matches, meaning that they could go up with the lowest tally since Crystal Palace in 2013. They head into this game as underdogs and will need another magical display if they are to end their wait for a Premier League return.