1900 BST, Friday 22 June, Kaliningrad Stadium (Kaliningrad), BBC 1
Fresh off the back of a rugged, important win over Costa Rica, the Serbs will feel as though their chances of progressing into the last-16 will be high.
Ironically, their optimism may be diluted slightly by their opponents' dogged performance against favourites Brazil, which rightfully earned them a point.
Before the start of the tournament, second place was deemed wide open, under the assumption that Brazil would comfortably top proceedings, though the Swiss' defiance will have tweaked their own odds slightly.
With Serbia still to face Brazil, who may themselves need a win to ensure progress on the final day, and Switzerland facing Costa Rica, this tie may well go a long way to deciding which team gets through, and which doesn't.
Last Time Out
Costa Rica 0-1 Serbia
Serbia got their World Cup off to the best possible start by recording a narrow victory over 2014's surprise package, Costa Rica.
In a predictably tight game that would always be short of any real clear cut opportunities, a moment of magic from the left foot of veteran left back Aleksandar Kolarov ended up being the difference.
A trademark, long-range free-kick from the right side of the box saw the ball sail over the wall and into the net, past a helpless Keylor Navas.
Newcastle United man Alexander Mitrovic was a familiar nuisance throughout, and on another day may have buried one or two of the half-chances presented to him by Sergej Milinkovic-Savic, the game's Man of the Match.
Brazil 1-1 Switzerland
Switzerland got their World Cup campaign off to an impressive start, holding Brazil to a 1-1 draw in a match in which they were truly tested.
The Brazilians were wasteful, and although the natural pressure built as the minutes ticked by, a customary solid, hard-working Swiss performance saw Vladimir Petkovic's men take a well-deserved share of the spoils.
Brazil took the initiative through a trademark Philippe Coutinho strike from outside the box, whose curling shot went in off the far post, leaving Yann Sommer stranded.
Switzerland responded well, though, and didn't allow Tite's side to dictate the play, with midfielder Valon Behrami important in the breakup of play.
Their efforts were rewarded early in the second period when Steven Zuber rose highest to power home a Xherdan Shaqiri corner. Brazil huffed and puffed as the game went on, though were limited to a handful of opportunities, courtesy of a solid defensive display by the Swiss.
Mladen Krstajic has no injury concerns ahead of the crucial clash and has no reason not to select the same XI that started in the win over Costa Rica.
Hot property youngster Sergej Milinkovic-Savic will look to build on a steady opening encounter after completing the full 90 minutes in the opening round win.
Vladimir Petkovic always has no fresh concerns before heading to Kaliningrad though an early stage yellow card to Valon Behrami may see him protected by his manager to avoid a suspension.
Haris Seferovic looks set to keep his starting spot up front after keeping Brazil's Thiago Silva and Miranda busy enough on Sunday night, though Breel Embolo could be brought in either to lead the line or play out wide.
Key Battle: Aleksandar Kolarov (Serbia) vs Xherdan Shaqiri (Switzerland)
Stoke City's Xherdan Shaqiri gave Brazil's Marcelo something to think about on Sunday evening, and the Swiss will look to the winger to get at Kolarov down the Serbian left flank.
Kolarov, too, likes to get forward and attack as much as possible, so Shaqiri must keep up with his defensive duties if the Swiss are to limit searching balls into Mitrovic.
KEY STAT: Shaqiri (4) made the joint-most dribbles of any Swiss player against Brazil.
Similarly, however, Kolarov must perhaps find a better balance between attack and defence to prevent Shaqiri finding space in behind him too frequently.
Shaqiri's ability to cut in from the right flank onto his left foot is no secret, though dealing with it is another matter. His pinpoint corner found the head of Steven Zuber, who had to only jump, and his performance gave Switzerland a much-needed attacking edge against Brazil.
KEY STAT: Kolarov made the fewest defensive actions of any Serbian defender versus Costa Rica.
Kolarov has an equally dangerous left side, and the Swiss must stay disciplined enough not to give away needless free kicks around their box.
Futures will be told
This game could have a say in the outcome of the group standings, and a win for the Serbians will see them safely through to the next stage with a game to spare.
For the Swiss, a defeat would all but eliminate them from the tournament, leaving them needing a big win over Costa Rica in their final game, coupled with the need for Serbia to beat Brazil.
A draw wouldn't be the end of their hopes though they would then need to beat Costa Rica, and then hope that Brazil beat Serbia in the third and final game - provided Brazil beat Costa Rica.
Due to the consequences of this game, this could be a somewhat cagey affair, with neither side willing to take the initiative in fear of losing. A draw benefits Serbia's quest for a place in the next round, though not Switzerland's. They can't afford to be passive.
Breaking down barriers
Sergej Milinkovic-Savic, heavily linked to a Lazio summer exit, was the Man of the Match against Costa Rica and a crucial element in breaking down their low block defence.
He was strong on the ball and displayed a wonderful range of passing. In fact, if Mitrovic could finish, Milinkovic-Savic would have ended the game with two assists.
However, that Costa Rican midfield was weak and the Serb found it easy to create space for himself, with time on the ball to pick the right pass.
Valon Behrami's intentions - and the rest of the Swiss, for that matter - were clear to see, with a total of ten fouls committed on Neymar through the game. They had a plan to stop him and they'll likely do the same to Milinkovic-Savic.
He needs to find a way to get in behind that midfield and play between the lines without them kicking him to pieces. He is, however, much stronger than Neymar, and fearless in getting stuck in.
Prediction: Serbia 1-1 Switzerland
Although the Brazilians are yet to hit their stride and get into their customary rhythm, Costa Rica's days may be numbered, leaving Serbia and Switzerland jostling for second - or even top - spot.
Both sides will know the permutations ahead of kick-off, and will have the luxury of getting underway after the other fixture has finished.
With so much at stake here, neither side will want to lose. Both midfields are filled with hardened ball-winners, so gaining control of the centre of the park and bringing in the wider players will be key to victory.
Listen to the RealSport football writers discuss all the action from Day 6 of the World Cup in Kremlins in the Basement: RealSport’s daily World Cup podcast.