MOSCOW, Russia — The world’s two greatest players and a crowd of pretenders enter the knockout stage of the World Cup on Saturday when Lionel Messi’s Argentina and Cristiano Ronaldo’s Portugal target a place in the quarterfinals.

Argentina, the beaten finalist four years ago, escaped by the skin of its teeth after a ragged group phase and will rely heavily on Messi when its ageing team faces France in Kazan.

The French, armed with Paul Pogba, Antoine Griezmann and wonder kid Kylian Mbappe, have failed to fire the imagination so far and must sharpen up fast to keep alive their hopes of adding a second World Cup to the title they won two decades ago on home soil.

Ronaldo tore out of the blocks in Russia, smashing a hat-trick in his first game against Spain. But Portugal’s problem against a Uruguay team with the meanest defense in the tournament could be its over-reliance on the 33-year-old five-time World Player of the Year.

Uruguay won the last of its two World Cups in 1950 but it has high hopes, thanks to its stingy defence and top-class strikers in Edinson Cavani and Luis Suarez.

The World Cup featured 122 goals in a frequently thrilling first phase and, following Argentina’s near-collapse and the stunning failure of title-holder Germany to advance past the opening stage for the first time in 80 years, the draw is lopsided.

France, Argentina, Portugal, Brazil and Uruguay are all gathered in one section of the competition, with only Spain among recent winners in the other half.

It means that if, for example, England can beat Colombia on Tuesday, it will fancy its chances of booking a potential semifinal duel against 2010 winners Spain.

Before the tournament, France was widely tipped for a run to the finals, but it failed to click so far, scoring just three times in three matches. One of those was a penalty and another an own goal.

“Our group games left a mixed impression,” France coach Didier Deschamps said Friday. “From tomorrow it’s a new start for us.

“It’s make or break. We don’t have any choice. We have to do everything possible to make sure it goes well for us.”

Messi has spent the tournament trying to hold his unbalanced and ageing squad together, even apparently bypassing coach Jorge Sampaoli to give coaching instructions in the 2-1 win over Nigeria that saved the South Americans from the same fate as the Germans.

He has scored only once and Argentina’s campaign so far has been defined as much by Diego Maradona’s increasingly erratic and emotional outbursts as by any signs they can reach the finals again.

Sampaoli urged his other players to give Messi as much help as possible.

“Leo has such clear vision when it comes to football that he allows us to see things that, sometimes, only a true genius sees,” he said on the eve of the match in Kazan.

“It’s often difficult to be at the level of such a great player. He’s a shining light for us all, and we have to do our very best to all try to be at his level.”

Pierluigi Collina, the chairman of FIFA’s referees committee, said he was pleased with the impact of the video assistant referee (VAR) system being used in a World Cup for the first time but that it did not mean all decisions would be perfect.

FIFA said VAR crews conducted checks on 335 incidents during the group stage, helping achieve a 99.3 percent rate of correct decisions.

“VAR doesn’t mean perfection,” Collina said.

“There could still be some wrong interpretation or even mistakes, so it’s a not a perfection that can be reached having implemented VAR.” AFP