England and Argentina are coming to spoil the favourites' World Cup party in Paris this weekend - and they could do exactly that.
France and South Africa, their respective opponents at Stade de France, are expected to meet in the final on Saturday week, but it all depends on how they react to being semi-final favourites.
It is quite weird, really, that England are there again, just one win away from reaching a second successive World Cup final.
They started the tournament really poorly, but managed to get through the pool stages and then had a good game plan against quarter-final opponents Australia which has set up a clash with the host nation.
The thing is with World Cups, you don't have to play outstandingly well to win them. What you do is you don't play badly and you don't make mistakes.
If you look at comparisons between England in this tournament and what happened four years ago, then they are similar.
England didn't play particularly well during the 2003 World Cup, but they galvanised their team, got momentum and were mentally very strong. There is not much difference this time around.
England will have no fear of playing against France. They play against them all the time - three times this year, for instance - and they will know the kind of atmosphere to expect on Saturday night.
But what England will need to do is play a more rounded game against France, because Les Bleus won't be as easy up front as Australia were.
The key will be the England pack, and how field position is dominated. England must get consistently good field position, and their attacking game against Australia was certainly a lot better than it had been.
England are definitely building, and someone like Jonny Wilkinson gives them a lot of confidence. Get field position, get penalties and Jonny will knock them over.
If England can turn their pressure into points, then they will turn the pressure of the game and occasion on to France.
France have been to Cardiff, beaten the tournament favourites New Zealand and everything is back on track for them. They are on their home patch again, and people would expect them to turn England over.
What England have to do is stop France's momentum early, and then things can turn quickly.
I expect a big kicking battle between two teams who know each other so well. It is going to be like a game of chess, with people waiting for the opponent to make mistakes.
England full-back Jason Robinson wins his 50th cap on Saturday, and he is one guy who can really cause trouble for the opposition with his ability to break out of defence. The stage is set for him.
Yes, you would have to favour France, but I think it will be close, maybe with only one kick in it. France, though, have got to handle the pressure and expectation, which they didn't do in the opening game against Argentina.
South Africa are clear favourites against Argentina on Sunday, and they are now overall tournament favourites with New Zealand having gone out.
Argentina will look to play a good pressure game and a good kicking game, but make no mistake, this is going to be a massive forward battle.
If Argentina can play with the same tempo they produced in the pool victory over Ireland, then they should create opportunities, but if it's the same tempo as the quarter-final against Scotland, they are not going to score tries.
Argentina will try to pressurise and frustrate South Africa, but it has to be mistake-free rugby for the Pumas. If they manage that, then their forwards are capable of getting on top.
I still question Springboks fly-half Butch James a little bit, so he is an area for Argentina to look at, while centre Francois Steyn can do something brilliant one minute, then cause a calamity the next.
France and South Africa are the popular choices to progress - but this time last week everybody probably thought the same about Australia and New Zealand.