Messi will be 35 when the next World Cup arrives at the end of 2022, shifted from its usual mid-year slot due to the heat expected in Qatar, while Ronaldo will be 37.
Russian Federation marks Messi's fourth World Cup, and was the last chance for glory on the world stage for the 31-year-old Argentine superstar.
However, the 1998 World Cup champions have slipped to +850 on the World Cup championship odds after opening the tournament at +700, and have also fallen to defeat in all four previous meetings with Argentina while scoring just one total goal.
Later on Saturday, two-time World Cup champions Uruguay battle reigning European champions Portugal as slim +180 chalk, while Sunday's action has Spain taking on host nation Russian Federation as a heavy -180 bet, and the surprising squad from Croatia clashing with Denmark as -120 favourites.
Mascherano, who has played at four World Cups, made his debut for Argentina in 2003 when he still hadn't played professionally for River Plate.
Portugal's goal was the first Uruguay had conceded in 597 minutes of football, dating back to their 2-1 loss to Austria in November.
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Cristiano Ronaldo was frustrated as Portugal lost to Uruguay.
French striker Kylian Mbappe: "It's flattering to be the second teenager to score twice in a World Cup match after Pele but let's put things in context".
In the event, third-ranked Belgium won, adding even more firepower to the top half, while if England can get past Colombia they will fancy their chances of reaching a potential semi-final against 2010 winners Spain.
He explained: 'We looked at different options in an important game and had to make a decision.
"He is a worldwide star, but you don't prepare for a match thinking about one player, but thinking about the team as a whole".
The Round of 16 continues with a pair of matches on Sunday.