Following a gutsy 1-0 win over Ulsan HD and a thrilling but narrow 4-3 loss to Borussia Dortmund, the South African champions find themselves walking a tightrope. Three points from two matches isn't enough to control their fate - not with Fluminense and Dortmund both sitting on four. And with head-to-head records the primary tiebreaker, Sundowns can't afford to share the spoils. It's simple: only a win will do.

Their opponents? Fluminense - top of Group F, unpredictable at the back, and stacked with talent. One of the marquee names: Thiago Silva. The 39-year-old defender, fresh from his European swansong, is more than a symbolic figure. He remains central to the Brazilian side's structure. For Sundowns coach Miguel Cardoso, there's an ironic subplot - he narrowly missed crossing paths with Silva back in 2004 at FC Porto, when Silva arrived just after Cardoso had moved on from the club's youth setup.

On the pitch, the Sundowns boss has more pressing matters than old connections. Chief among them: keeping Lucas Ribeiro Costa under wraps. The Fluminense forward lit up the match against Dortmund with a dazzling solo goal and is capable of punishing even the slightest lapse.

And lapses have hurt Sundowns. Despite showing real attacking flair against Dortmund - clawing their way back from 4-1 down to 4-3 - defensive errors proved costly. Goalkeeper Ronwen Williams' loose pass gifted Dortmund their opener, and the back line struggled to recover. But Sundowns didn't crumble. Iqraam Rayners and Lebo Mothiba gave them a lifeline with late goals that nearly sparked a comeback.

Fluminense, too, showed vulnerabilities - trailing Ulsan 2-1 at halftime before surging back to win 4-2. Their defense isn't impenetrable, and that will give Sundowns hope.

Nicknamed The Brazilians for their style and yellow-and-blue kit, Sundowns will need to channel the samba spirit and then some. While Fluminense require only a draw to progress, Sundowns are chasing something far more elusive: belief, precision, and a performance for the ages.

All roads lead to kickoff - and for Sundowns, every pass, every tackle, every moment could be the difference between heartbreak and history.

Mamelodi Sundowns set for do-or-die duel with Fluminense in Club World Cup showdown