The general consensus is that one of these two teams will finish as runners-up to Brazil in Group E.
Serbia began perfectly: a 1-0 win over Costa Rica, thanks to a stunning Aleksandar Kolarov free kick, put them in a strong position with two games left to play.
Switzerland, meanwhile, were impressive in a game many expected them to lose heavily. A resolute defensive performance kept Brazil at bay and set things up nicely for a potentially decisive clash with Serbia.
The onus will be on Switzerland to take the game to Serbia although the game is unlikely to be an open and expansive one.
In a game that could decide who progresses into the Round of 16, here are three key battles to look out for:
1 Sergej Milinkovic-Savic (Serbia) vs Valon Behrami (Switzerland)
Sergej Milinkovic-Savic, perhaps unsurprisingly, was Serbia's standout performer against Costa Rica.
The powerful 23-year-old with a deft touch and impressive technical attributes proved a constant threat as the number ten in Serbia's 4-2-3-1 system.
The Lazio man might have had a couple of assists to his name had it not been for the profligacy of Aleksandar Mitrovic. Twice he played in the Newcastle forward and twice Mitrovic squandered the opportunities.
If Milinkovic-Savic replicates that performance against Switzerland, he should get more reward.
But he will perhaps not be granted as much space. Switzerland midfielder Valon Behrami has already expertly restricted Brazil's Neymar and will be looking to frustrate Serbia's danger man in a similar fashion.
The former West Ham man was forced to withdraw after 70 minutes of the Brazil game with a thigh strain. But he is expected to be fit to play against Serbia. "We need him," said Switzerland coach Vladimir Petkovic.
2 Xherdan Shaqiri (Switzerland) vs Nemanja Matić (Serbia)
Xherdan Shaqiri did not play particularly well against Brazil - and earned some frank criticism from ITV pundit Gary Neville as a result. When on form, though, he remains Switzerland's most dangerous attacking player.
He should see more of the ball against Serbia and will look to cut in from the right and drive at the opposition's backline.
Shaqiri's directness, his ability to occupy defenders, will be key if Switzerland are to threaten a Serbia side that did not always convince defensively in qualifying.
The areas in which Shaqiri looks to find space will be covered by Nemanja Matic who is the more defensive of the midfielders in Serbia's double pivot. Matic is, unlike Shaqiri, not diminutive.
He is an imposing presence in front of the defence and will look to act as a shield to prevent Shaqiri, and Switzerland's other forward players, from finding space.
3 Dusan Tadic (Serbia) vs Ricardo Rodriguez (Switzerland)
Dusan Tadic, who plays on the right of a dangerous Serbia front four, impressed against Costa Rica.
His late-season form for Southampton, it appears, could be continuing at the World Cup.
If he is to have an influence against Switzerland, Tadic will need to avoid the attention of left back Ricardo Rodriguez who plays his club football with Milan in Serie A.
Tadic, too, might need to be aware of his defensive duties. Rodriguez likes to push forward and it would be unwise to allow him space on the left flank.
The 25-year-old is technically proficient; often associated more with attacking attributes than defensive attributes.
Rodriguez scored the only goal in Switzerland's playoff victory against Northern Ireland and then cleared a last minute Jonny Evans header off the line in the second leg.
On Friday, whoever prevails in the battle between Rodriguez and Tadic on that side of the pitch could have a decisive impact on the game.
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