The victor on Saturday will rub shoulders with the likes of Pep Guardiola's Manchester City next term but the "biggest ever financial prize in football" is also at stake, say financial analysts.
Promotion to the Premier League for either club will see an uplift in revenue of at least £170m, according to Deloitte's Sports Business Group, and at least £290m if they survive their first season.
The experts also predict an increase in revenue for 2016/17 could propel Middlesbrough or Brighton into the world's top 30 revenue-generating clubs.
It doesn't get much closer than two glory-chasing sides level on points going into the final afternoon but who will prevail in front of the Sky Sports cameras? From the form book to the expert view, here's all you need to know...
What's the deal?
Championship top three
It's pretty simple. Three points would secure promotion to the top flight alongside Burnley and the winner could still seal the title.
If the Clarets lose to already-relegated Charlton at The Valley, a winner at the Riverside would see that side promoted as champions with 91 points to Burnley's 90. If Sean Dyche's men win in south London, though, they will take home the silverware.
A draw would be enough for Middlesbrough as they have a superior goal difference.
Bu it isn't all doom and gloom for the losing side. They would face sixth-placed Sheffield Wednesday in the play-offs - with home advantage in the second leg - and could still earn promotion to the Premier League.
Who's in form?
Both sides are in decent form, but missed out on the chance to take maximum points last weekend. Middlesbrough drew with Birmingham on Friday, while James Wilson's late strike earned Brighton a point against play-off contenders Derby on Monday.
But they are both still on unbeaten runs. Boro have not lost in nine but have drawn the last three - including a 1-1 result against Burnley.
The Seagulls made history at the start of the season when they went on a run of 21 games without loss - but were stopped in their tracks with a 3-0 home defeat to Middlesbrough just before Christmas.
Since a 4-1 loss to Cardiff at the end of February, Brighton are now unbeaten in their last 13 Championship encounters, winning five of the last six.
Any injuries to worry about?
Karanka is unsure over the fitness of defender George Friend, who suffered a hamstring injury at Turf Moor last month.
Karanka confirmed the club's medical staff will assess Friend on Saturday morning, but does not anticipate doubts over other players.
Ritchie de Laet stands by to step into the defence for Boro should Friend fail to make the cut.
Brighton will be missing defender Lewis Dunk, who starts a two-match ban following his red card against Derby on Monday.
That means a first appearance since January for club captain Gordon Greer alongside Connor Goldson at centre-half.
Any omens from the stats?
Boro have won three of their last four league encounters with the Seagulls (D1).
Brighton have not conceded a goal in any of their last three trips to the Riverside, winning two (D1).
Boro have kept more clean sheets in league competition than any other team in the top four tiers this season (22).
Tomer Hemed's 17 goals have won Brighton 16 points this season; only Andre Gray's goals (22 points won) have been more valuable.
Brighton have scored the first goal in more matches than any other team this season (28); with Chris Hughton's men avoiding defeat in all of those games (W21 D7).
Are the managers confident?
Seagulls boss Chris Hughton is backing his side to do the business and was in bullish mood following Monday's draw with the Rams.
"We will be going there with a winning mentality and we need to show enough quality," he said. "There's no doubt Middlesbrough will be the favourites and they'll be pleased with our result, but we've given ourselves every chance.
"We have been good away from home for the majority of the season and we haven't lost today. It is a big task but not one that is impossible."
Boro boss Aitor Karanka is hoping home advantage pays dividends and believes his side are better than the one that suffered an agonising play-off final defeat last season.
"We have this game at home in front of our support and I am really positive," he told the Gazette.
"We have it in our hands. We have the final at our own stadium and we are better than we were last season.
"It will be a really tough game, a really difficult 95 minutes. But we ready. I am ready, the club is ready, the fans are ready, and especially the players are ready.
"It will be tough but I think if I had to choose Brighton's situation or ours I would choose ours, definitely."
What's the expert verdict?
Sky Sports Football League expert Ian Holloway will be at the Riverside and describes the showdown as a "double final".
"I can't believe I'm fortunate enough to go. I can honestly tell you I don't know which way it's going to go," he said. "I don't know who's going to handle the pressure of it that well. I urge the Middlesbrough supporters to get right behind your team. I know they want it really badly and it's been a long time since they dropped out of it [the Premier League].
"Chris Hughton and his Brighton team know they've got to win. Sometimes worrying about a draw - it stops you going for broke so sometimes it's better to know what you've got to do.
"The game will be won or lost in the nerves and who can play the occasion. Who can go through the process rather than be caught up in the emotion of the game. It's like a tug of war and it's a one off - like a double final for the neutrals this year.
"Middlesbrough have got the chance to put the play-off final from last season behind them. Will that carry into this year? I hope not, but truthfully I can't wait to see and the atmosphere will be something else and I just know someone's going to be disappointed.
"If it's Brighton, they will be more than delighted with their season anyway and I think they'll fancy their chances with the way their team is playing. If it's Middlesbrough who miss out, I'm sure that it would be harder for them because of last season. I feel for whoever doesn't do it, but they've all had great seasons and I can't wait to see how it unfolds."
Who do you think will be taking the final automatic promotion spot to the Premier League? Let us know in the comments below or tweet us @SkySportsFL.