The opening 90 minutes contained talking points and drama aplenty, but in the end it was Los Blancos who came out on top to find themselves clear favourites to lift the trophy for a 10th time.
While the first half in Catalonia may have failed to truly live up to the pre-match hype, what followed in the second 45 had the 89,514 spectators inside the ground - and millions more around the planet - completely gripped.
The final 15 minutes of the match in particular have been debated in the days between the two legs, as Cristiano Ronaldo came off the bench to score a fine individual goal before being dismissed in controversial circumstances, ruling him out of not just the return match but also his side's opening four league games.
That the second yellow shown to Ronaldo was awarded due to a perceived dive, despite clear contact from Samuel Umtiti, particularly hurt boss Zinedine Zidane as Luis Suarez had won a penalty for his side moments beforehand when seemingly conning the officials.
With the dust settled on the first leg La Liga holders Madrid are good value to begin the new season with yet another piece of silverware, with Zidane racking up the trophies at an incredible rate during his 19 months at the club.
On top of winning La Liga last season, when successfully holding off the challenge from Barcelona that went right down to the wire, Zizou has also lifted back-to-back Champions Leagues, two UEFA Super Cups and the FIFA Club World Cup.
For all the accusations of Zidane simply taking over a hugely talented group of individuals, no other Madrid manager since 1958 has been able to guide the club to the top of both Spanish and European football in the same season, as was the case in a memorable 2016-17.
The challenge for Madrid is to remain motivated enough to achieve that feat once again, while also progressing further than the quarter-finals in the Copa del Rey - won by Barcelona - in the upcoming campaign, which could go down as the greatest in the capital side's history.
Zidane may still be in the market for new recruits, having so far brought in just Dani Ceballos and Theo Hernandez - both subs in the first leg - and lost the likes of Danilo, Alvaro Morata and James Rodriguez, arguably making his squad weaker than a few months back.
Either way, two competitive wins from two against Manchester United and Barcelona in the past week suggests that Madrid's dominance is not yet about to slide, providing an ominous sign for sides watching on around Europe - not least arch-rivals Barca.
Recent form (including pre-season): LLLWWW
Even before Sunday's disappointing defeat to Madrid on home soil, there was already a sign that the aura that has surrounded Barcelona for so long has now almost completely faded.
Their transfer business alone this summer sums that up well, with Brazilian midfielder Paulinho being brought on board this week - despite resistance from supporters - to join Nelson Semedo and Gerard Deulofeu in signing permanently during the summer.
Throw into the mix the loss of one of their true superstar players in Neymar and you can see why fans are a little concerned, giving boss Ernesto Valverde an almighty task in his first year at the helm after taking over from Luis Enrique in May.
With a little over two weeks of the transfer window still to go it is almost certain that Valverde will further strengthen, though, as rumours linking the Catalans with moves for Ousmane Dembele and Philippe Coutinho refuse to go away.
The bad news is that both Borussia Dortmund and Liverpool are reportedly holding out for £100m+ deals, knowing that Barca are sitting on a large sum of money received from Neymar's shock departure to Paris Saint-Germain in a world-record deal.
Even with Neymar in their ranks, Barcelona were far from their best in Enrique's final campaign in charge, missing out to Madrid in La Liga and exiting the Champions League to Juventus in the quarter-finals, even if they did pull off the greatest of comebacks against PSG a round prior.
Now, after losing his first official match in charge, Valverde has to get his players in the right frame of mind to improve on 2016-17, which did ultimately end on a positive note thanks to a 3-1 victory over Alaves in the final of the Copa del Rey.
Barca actually enjoyed a positive pre-season campaign leading up to the first-leg loss at Camp Nou, overcoming Juventus, Manchester United, Madrid and Brazilian club Chapecoense, but they were not at the races in their first competitive outing of the summer.
The Supercopa de Espana's most successful side, with 12 titles to their name, require a much-improved performance on Wednesday night if they are to extend their record of wins, though on the basis of the past 12 months the power of balance appears to have well and truly shifted to the capital.
Recent form (including pre-season): WWWDWL
Real will likely appeal the red card shown to Ronaldo at the weekend but his shove on referee Ricardo de Burgos Bengoetxea will still cost him dearly, adding a further four matches to the automatic one-game ban.
Starting without the Portuguese is something Madrid's players have become accustomed to of late, however, as he is slowly being eased back into action following his Confederations Cup exploits in June.
In his absence, Gareth Bale and Karim Benzema failed to really click into gear for large parts at Camp Nou, with support being offered by the livelier Isco in a free role, though Marco Asensio again impressed from the bench by scoring and could fill in for the latter.
As far as the visitors are concerned, Gerard Deulofeu has failed to truly make the most of his big chance on the left of the front three, so Denis Suarez may be given the nod for this one.
New signing Paulinho is not expected to play any part at the Bernabeu, but another of the new recruits in Semedo could well provide some fresh legs at full-back in place of Aleix Vidal if Valverde opts to rotate slightly.
Real Madrid possible starting lineup:
Navas; Carvajal, Varane, Ramos, Marcelo; Kroos, Casemiro, Modric; Isco; Bale, Benzema
Barcelona possible starting lineup:
Ter Stegen; Vidal, Pique, Umtiti, Alba; Gomes, Busquets, Rakitic; Messi, L.Suarez, D.Suarez
Head To Head
Sunday's encounter at Camp Nou was the 267th time the two sides have faced off, with Barca still boasting the superior record - 111 wins to Los Blancos' 98.
Despite the two-goal margin it is still all to play for on Wednesday, although the Catalans have never managed to pick up an away win against Madrid in this competition.
We say: Real Madrid 3-1 Barcelona (6-2 on agg)
Even when boasting a man advantage in the first leg, Barca were left horribly exposed at the back when pushing players high up the pitch, allowing Los Blancos to add a potentially killer third through Asensio late on. It could be a similar story in this latest showdown, with Los Blancos perfectly set up to expose their opponents on the counter.