There is a real contrast in styles in both Championship play-off semi-finals - and Derby must enter their tie as favourites, given their league form and goal-scoring prowess.
Chris Martin's 20+ goals are a reflection of an outstanding individual season and County's wonderfully gifted midfielders have been able to feed off him, including Craig Bryson.
Bryson, who has 16 goals and multiple assists this term, is my pick for Championship midfielder of the season and could once again be the Rams' central figure in this two-legged tie with Brighton.
Albion left it nail-bitingly close to secure the final play-off spot, with Leonardo Ulloa underlining his importance to Oscar Garcia's Gulls by scoring a last-minute header against Nottingham Forest.
The Argentine will be pivotal in the clash with Derby and Brighton will be hoping Will Buckley and Kazenga LuaLua can provide the width and service for the powerful hitman.
Fluid and free-scoring Derby against a more defensively-minded and resolute Albion is one of two fascinating fixtures, with the other QPR versus Wigan.
After a very strange season with intense media scrutiny and wholesale squad changes, Harry Redknapp's Rangers now understand you can take nothing for granted in the Championship.
The Hoops could surprise everybody, breath a huge sigh of relief, and perform to their potential in the play-offs and their chances have increased considerably by the return from injury of the prolific Charlie Austin, as well as winger Junior Hoilett.
Also key will be the form of Niko Kranjcar and the availability of mercurial midfielder Ravel Morrison - who in his loan spell has had a massive impact, adding pace, enterprise, and a real goal threat, something that was lacking in the Londoners' engine-room before.
Wigan have limped into the play-offs, quite literally, but it has been a marvellous season, taking into account the slow start and the physical stress put on the squad by the European and FA Cup campaigns.
Uwe Rosler has had to chop and change and rest players due to fatigue but he has the man-management skill and tactical nous to reinvigorate and rejuvenate his troops before Friday's first leg.
Concession of goals will weigh on Uwe's mind, despite wholesale defensive changes, but Wigan, like Derby, possess real creativity and more match-winners than their opponents.
The Latics have a plethora of frontmen, wide and central, who will at some point take centre stage.
Nick Powell and Martyn Waghorn have made big impacts, as both are clever with their movement and ability to create space in the penalty area, while Jordi Gomez possesses a brilliant strike from dead-ball situations or open play.
But the player who could potentially match QPR's Morrison for magic moments is Callum McManaman.
Strong and direct at times, but also a very good dribbler and two-footed to boot, McManaman's duel with Benoit Assou-Ekotto could be key to Wigan's success.
So will it be the more solid and pragmatic approaches of Brighton and QPR that sees them through these two-legged tussles, or will the more maverick, expansive and fluid plans of Derby and Wigan book them a place in the final?
Let the games begin!
CHAMPIONSHIP PLAY-OFFS ON SKY
Brighton v Derby (7.30pm, Thu, Sky Sports 1)
Wigan v QPR (7.30pm, Fri, Sky Sports 1)
Derby v Brighton (5pm, Sun, Sky Sports 2)
QPR v Wigan (7.30pm, Mon, Sky Sports 1)