Argentina are also expected to notch another victory when they take on Nigeria in Group F in home of a vociferous support.
Matt Brocklebank, meanwhile, looks at the Group E matches and he's siding with the Swiss for their clash with Honduras.
Check out our match-by-match verdict.
Bosnia had been most people's picks to qualify alongside Argentina in this group but, with this game still to play, they are already out.
There are plenty of suggestions that they will subsequently field a much-changed team in this one with some reports saying some players aren't keen to play in what, for them, is a dead rubber.
While the Bosnians have failed to live up to expectations (although it should be noted they were not helped by the officials in their defeat to Nigeria), Iran have arguably exceeded theirs.
That may sound strange given they have yet to score but their defensive solidity has been impressive in both games so far with the only goal conceded being a Lionel Messi wonder strike.
That cruel, late blow denied them a point they deserved but they remain in the hunt for a last 16 place although they will need to win this contest to stand any chance.
The Iranians also showed in that Argentina match what they can offer going forward with their counter-attacks close to producing a goal on more than one occasion.
That could be a problem for Bosnia here. They looked vulnerable when Nigeria broke on them last time out and that deficiency is effectively what eliminated them from the tournament.
While the Bosnians did create plenty against Nigeria only to fluff their lines - Edin Dzeko could easily have had a hat-trick - I don't think chances will be as easy to come by against this Iran defence.
I'd expect Iran to keep things tight early on - chasing an early lead simply isn't boss Carlos Queiroz's style and won't suit how they set up.
They will try to play on the break and can expected to only really force things if it's still all square heading into the final 20 minutes or so.
Draw/Iran in the HT/FT market at 15/2 looks a fair shout, while at the prices I'm also much keener on Iran at 11/4 than I am on Bosnia at 23/20.
However, I'm going to chase a bigger prize by backing Iran to win 1-0. Given their style of play, if they are going to win this game then this scoreline has to be favourite.
Verdict: Bosnia-Herzegovina 0 Iran 1 (AS)
Best bet (with Sky Bet): Iran to win 1-0 at 9/1 (Price Boost offer)
Argentina fans are set to pour across the border and into Porto Alegre for this match and make it effectively a home game for them.
They could do with their support as so far they've frankly been a tad disappointing.
On another day, Bosnia might have got something from the two sides' game and only a Lionel Messi wonder goal in injury time got Argentina past Iran.
Of course, it's about getting things done and Argentina have taken six points from six on offer. But, like Brazil on Monday night, they will be keen to put in a performance ahead of the last 16.
It is this element which puts me off backing a draw - a result which would suit both sides and one offered at a tempting 3/1. A point takes Argentina through as group winners and also ensures Nigeria move into the last 16.
It's certainly a result for the conspiracy theorists to mull over.
Nigeria should not be dismissed lightly having produced a much better display against Bosnia than they did in their opener against Iran.
Stifled by the Iranians' defensive approach, they were much happier hitting Bosnia on the counter-attack and seem likely to apply the same tactics again here with an unchanged XI being touted.
They offered enough against Bosnia to show they could get at Argentina, who conceded chances as they pushed forward against Iran.
However, Nigeria were not at all solid at the back and Bosnia created plenty only for Edin Dzeko, in particular, to show uncharacteristic profligacy. Argentina seem more likely to punish them if a similar scenario unfolds and so I'm in agreement with the layers who expect a win for Alejandro Sabella's side.
So how to get with them?
I'm afraid my suggestion is unoriginal, but one which makes plenty of sense and hopefully will reap rewards.
I'm certainly surprised to see odds-against quotes about Lionel Messi scoring at any time.
Everyone knows his ability but he's proven it on the big stage with a fantastic goal in each of his games in Brazil so far.
Messi, who celebrated his 27th birthday on Tuesday, has been the man to bail Argentina out when they've needed it and it's worth remembering that the rest of the fabled attack - Sergio Aguero, Gonzalo Higuain et al - has failed to produce a goal.
Verdict: Nigeria 1 Argentina 3 (AS)
Best bet (with Sky Bet): Lionel Messi to score and Argentina to win at 8/13
Any football match in which there is a possibility one side's goalkeeper could at some stage be seen trying to get on the end of a corner in the opposition penalty area must be approached with caution by punters.
Both of these teams can still qualify for the round of 16, depending on what goes on between Ecuador and France, but I fully expect the French to complete the job in style, which would mean Switzerland only require a draw.
However, if Ecuador look like getting something out of their match, then the Swiss will need to push for a win and Honduras certainly aren't going to make it easy for them.
Luis Fernando Suarez, former Ecuador manager and current head coach of Honduras, will have taken plenty of positives from their 2-1 defeat to his old side on Friday, not least the fact they were able to keep all 11 men on the field.
Wilson Palacios will come back into the team after serving his one-match ban for being sent off against France and it's not hard to envisage the World Cup minnows frustrating Switzerland from the outset.
Priced up at 8/1 to claim all three points, it must not be forgotten that Honduras were just seconds away from holding France 0-0 at half-time, while they went into the break at 1-1 with Ecuador having given as good as they got.
Switzerland have, thus far, shown signs of naivety, finding themselves a goal behind after half an hour in each of their first two matches.
What will have encouraged manager Ottmar Hitzfeld, however, is the way his team have finished games as they dug deep to get the result against Ecuador and scored twice in the last 10 minutes of the France game, albeit when Didier Deschamps' outfit had slipped into cruise control.As touched upon in the opening paragraph, stakes must be kept low in games which could end up being frantic, but Switzerland are slow starters and are facing a defensively-minded unit so I'd be very surprised if they had the game sewn up at an early stage.
Prices around 12/5 against 0-0 at half-time are tempting but the Swiss have enough quality to ultimately stamp their authority on the tie so odds around 3/1 for them to claim all three points after drawing at the break are preferred.
Verdict: Honduras 0 Switzerland 2 (MB)
Best bet (with Sky Bet): Draw/Switzerland in HT/FT market at 3/1
There's a decent case to be made for France being the most impressive team we've seen at these World Cup finals so far.
Didier Deschamps' new-look side didn't set the world alight in the first half-hour in their opening game against Honduras but there was a strong sense that they firmly had matters in hand before Karim Benzema's penalty just before the break put them in complete control.
Often slow starters under Deschamps in the past, Les Bleus laid that criticism to rest with a blistering opening 20 minutes against Switzerland and although a defensive wobble saw the Swiss restore some pride late on, France have done very little wrong in their two games.
They have all but qualified for the last 16 and only need a draw here to confirm top spot in Group E.
Odds of 5/6 to claim maximum points against a fairly limited Ecuador side look about right and it's no surprise to see France/France being heavily supported in the half-time/full-time market.
Benzema is the standout option to open the scoring and tops the betting at 4/1 but what was obvious in the Switzerland game, when there were five different scorers, was that this is no one-man team in an attacking sense.
Benzema now has three goals in the tournament and will be keen to kick on for the top-scorer gong, but if you want the Real Madrid striker on side then the safer option may be to back him at a shade of odds-against in the anytime market.
Ecuador's three goals have all been scored by Enner Valencia and he can be supported at 3/1 to maintain his hot streak.
Currently playing his football for Pachuca in the Mexican top flight, there will be plenty of clubs showing interest in the 25-year-old, even if Ecuador are heading home after Wednesday's match.
That looks likely to me, with France expected to keep up their perfect record, although the layers are taking few chances and it might be a game to sit out and wait to see who they face in the first knockout stage.
Verdict: Ecuador 1 France 4 (MB)
Best bet (with Sky Bet): Karim Benzema to score any time at 4/5