If ever a "12th man" were needed, this winner-takes-all shootout provides the setting for it. Atleti will have just 300 travelling fans behind them in their quest for a draw which will hand them a first La Liga title since 1996.
Per Sid Lowe of The Guardian, this is only the third time in Spanish football history that rivals for the title have gone head-to-head on the final day. It promises to be a fascinating 90 minutes, and Diego Simeone's tactics are likely to largely dictate the pattern of the game.
Whilst it would be anathema to his principles, Simeone is well aware of Barca's recent struggles against teams who "park the bus" and as such, he may decide to set a defensive stall out from the beginning.
With only a draw required, Atleti can afford to sit back and punish Barca on the counter. However, such negative tactics could work against the Rojiblancos as the Catalans go all out for the three points they need to retain the trophy.
And fortune favours the Catalans:
Camp Nou is sold out and will be buzzing in anticipation of a defining victory for the home side. What better way for Carles Puyol to end his playing career than parading another La Liga before an adoring set of home fans, swathed in Blaugrana.
Tom Conn of Inside Spanish Football notes that Barcelona's talismanic captain is doing everything possible to be fit for his final bow.
Gerard Pique has only trained once since his injury against Atleti some six weeks ago, but according to Mundo Deportivo via Matt Law of SportsMole has an outside chance of standing shoulder to shoulder with his old sparring partner for one last adventure.
Given Marc Bartra's form over the last few weeks however, it would be a mistake to even consider a relatively unfit Pique for such a high-profile game.
As with Pique and Puyol, left-back Jordi Alba also faces a race to be fit but with Adriano Correia proving more than an able deputy, it again makes little sense to rush players back for the sake of it.
Tata Martino may well be presiding over his final Barcelona XI, and may feel that a last-throw-of-the-dice change in tactics will win him the game. Five times he has used the 4-3-3 formation against Atleti and five times it has failed.
If ever there was a time to experiment with an attacking 4-2-3-1, then Saturday is it.
Sergio Busquets expertly protecting his back four, allowing Xavi Hernandez the time and space required to feed the front four.
Lionel Messi hasn't enjoyed his battles against the mattress makers this season, but in all of them, he has been played centrally and had no room within which to work.
Moving him to the right is what could win Martino the game. A more dangerous proposition out wide, he benefits from the opportunities to drift inside, or play short, quick ball and get in around the full-backs.
Alexis Sanchez as the nine, with Cesc Fabregas just behind give Barcelona an aerial presence and a creative one, Cesc being adept at controlling the knock downs and moving play into more dangerous areas. With Iniesta's dancing feet on the left, Barca have a genuine attacking threat right across the pitch.
Against a team that have buckled under weighty expectation in the last two games, Barca need to exert sustained pressure over 90 minutes to give themselves a chance of winning what seemed impossible just a few short weeks ago.
It's now or never, Tata.