Who will win the world cup?

Picking a World Cup winner is just as tricky now as ?

Argentina scrambled through to the last-16 with a late winner against Nigeria on Tuesday but with Germany already out, they aren't the only major contender who have struggled to find their stride in the group stages.

More than two weeks into the tournament, we're still waiting for a top tier favorite to deliver a statement victory or commanding performance.

Brazil? They were held by a Switzerland side who scraped past Northern Ireland in the play-offs to make it to the World Cup before needing two injury-time goals to beat Costa Rica and seeing off Serbia.

Spain? Julen Lopetegui's sacking on the eve of the tournament disrupted their preparations and their qualification to the last-16 was in the balance until the very final moments of their draw with an already-eliminated Morocco.

Spain only took five points from their group games
As for France, they needed favours from VAR to beat Australia before being booed off after their stalemate with Denmark in their final group game, while Portugal have leant heavily on Cristiano Ronaldo to make it to the knockout phase.

Group G rivals Belgium and England - who were the level below the top contenders according to the bookies - have arguably had some of the most eye-catching results, but neither side looked like world-beaters in their lacklustre meeting on Thursday.

Of course, there is plenty of time to grow into the World Cup - Spain famously lost their 2010 opener to Switzerland before going on to victory - and importantly all of the big guns with the exception of Germany have found a way through to the knockouts, however unconvincing they have been at times.

Gareth Southgate's side were beaten by Belgium on Thursday
But rewind to 2014 and by the end of the group stage three of the eventual final four had delivered attention-grabbing wins and underlined their credentials to go the distance.

Germany, who went on to win the title, had thrashed Portugal 4-0 in their opening match. The Netherlands had routed defending champions Spain 5-1. Brazil had swatted aside Croatia 3-1 and Cameroon 4-1. Only Argentina, runners-up in the end, had struggled through the first phase.

It makes for an intriguing next stage - and, after the prelude of the group stage, the favorites will now have to find their best form. Could it be a year for one of the outside contenders lift the trophy?