There are just three weeks left of the Rugby World Cup, and the knockouts begin this weekend with four blockbuster quarter-finals set to take place across France.

All of the matches offer truly exciting match-ups: all four of the big favourites are pitted each other, while it's difficult to chose any winners from the games involving the remaining four nations.

The market has France and Ireland as joint 3/1 favourites to win the competition, and that seems fair given they were the two most impressive sides from the pool stage. With the way the knockout brackets are set up, a France-Ireland final is seen as the most likely at 7/2.

Both are favourites in their quarter-finals, but you can expect them to have to dig deep if they want to progress - margins of victory in both their quarter-finals likely will be no more than 6-10 points.

For France in particular, the challenge is stark as they take on South Africa on Sunday evening at the Stade de France.

South Africa are World Champions for a reason, and if they had their kicking boots on against Ireland then this meeting would have been more likely the final.

The hosts are 5/6 to beat the 5/4 Boks in a game that will be dominated by heavy hitting forwards, but that may well be decided by which set of backs prove more clinical.

In that category the French have been the more impressive and, if the forwards can hold off the South African bomb squad in the same way Ireland did, then the Stade de France should be celebrating victory come Sunday night.

Even without Antoine Dupont - who faces a race against time to be fit - there are star names across the backline of the home nation. Full-back Thomas Ramos has kicked more points (61) than any other player this tournament, Gael Fickou continues to be the definition of a solid centre and Damian Penaud is on the brink of making history.

Penaud is the danger man South Africa must keep an eye on. With six tries, he is two away from matching the tournament record for tries in a single World Cup. He has been clinical, but so too has the entire backline in creating chances for him.

He is 7/5 for the tournament's top tryscorer, and should be looked at for anytime tryscorer in the game against South Africa.

In the other headline match, Ireland take on New Zealand on Saturday evening as they attempt to overcome their quarter-final hoodoo.

For the Irish, there is an ominous sense of "if not now, when?" Not only is this their greatest ever side, but they have defeated the Kiwis in three of their last four matches (including a series win in New Zealand) and as such they are 7/9 favourites to beat the 13/10 All Blacks.

They have a pack that is able to go toe to toe with anyone and a backline that, at its best, plays fluid rugby historically only displayed by their opponents.

Nerves among media and fans have grown, and you wonder what the feeling within the camp is. There are near hourly updates on the state of three big injuries; second row James Ryan is to see a specialist about his hand injury, while both starting wings in Mack Hansen and James Lowe were forced off against Scotland. If any combination of two from those three are unable to line up in the starting XV (particularly if both wings miss the match), Ireland's edge over the Kiwis will be severely damaged.

It would be wrong to talk about Ireland without mentioning one of the players of the tournament so far, centre Bundee Aki. He has looked a player possessed with four tries and leading the tournament with 61 runs made while he also has the second most clean breaks with nine.

For the Kiwis, the challenge concerns whether their forwards can stand up to Ireland's. Whilst the backs have scored big in the pool stage games against Namibia, Uruguay and Italy the pack cannot be said to have faced much of a challenge since their opening day 27-13 loss to France, when to all intents and purposes they crumbled.

Just as Ramos punished their mistakes from the tee that day you can expect Johnny Sexton to do the same again if opportunities arise.

Just before the Ireland-New Zealand game, 4/7 Wales take on 7/4 Argentina in what both sides will see as a winnable match.

Los Pumas have not turned up to this tournament in quite the way expected, typified by their lacklustre loss to 14-man England in their opening pool game. They showed fight against Samoa and Japan, but that second game in particular would not have been so close if they had tightened up their discipline.

It will be an altogether different challenge against Wales. The impressive back row Jac Morgan will lead the Welsh pack into battle against the Argentine forwards, who will be without Pablo Matera.

The Welsh backs will fancy their chances - Louis Rees-Zammit will aim to get on the score sheet, while Dan Biggar will look to rack up the points from the tee.

The last quarter-final to talk about comes on Sunday afternoon, when England face off against Fiji in a game of contrasting styles which feels too close to call.

The market heavily leans towards England who are priced at 1/3, with Fiji at 5/2. That feels somewhat unfair for the flying Fijians; their 30-22 win at Twickenham in the warm-up to the tournament will give them hope and is one of their greatest wins in history, topped only by their 22-15 dispatching of Australia earlier in this tournament.

Admittedly their loss to Portugal in the final pool game marred what had been a solid start to the World Cup, but the Fijians will no doubt give their all against an opponent they know they can beat - and as such a win for either side will likely be by only 6-10 points, or even less.

England will no doubt try to kick their way to victory as they have the whole tournament, but this is their first real challenge after an easy pool stage.