MOSCOW — Lionel Messi is going to have a hard time keeping up with Cristiano Ronaldo at this year's World Cup.
The Argentina great had a penalty kick saved during his team's tournament-opening 1-1 draw with Iceland. At 31, this could be Messi's last World Cup, and Thursday's match against Croatia is crucial as the longtime Barcelona forward tries to deliver his first major title for Argentina.
Messi's biggest rival, Ronaldo, seems less burdened during what could also be his final World Cup run.
Ronaldo has scored a tournament-leading four goals — all of Portugal's goals so far — while silently needling Messi. After his first goal, the 33-year-old Ronaldo stroked his chin, implying that he was the "GOAT," an acronym for "greatest of all time." Messi is featured in ad with a real goat.
And when Ronaldo took the field for Portugal's 1-0 win over Morocco, he sported a goatee on his previously clean-shaven chin. He promptly scored with a header in the fourth minute.
Croatia leads Group D after its 2-0 win over Nigeria, and another victory would put Argentina in a precarious position. Veteran midfielders Luka Modric and Ivan Rakitic shined in the opener, with Modric scoring one goal and setting up another.
Croatia hasn't advanced past the group stage since 1998, and this could be the last chance for Modric, Rakitic and Mario Mandzukic, all of whom are over 30.
Another veteran provided a bit of drama for Croatia. Coach Zlatko Dalic sent home Nikola Kalinic because the striker wouldn't come off the bench as a substitute. The team will continue with 22 players.
Croatia and Argentina play Thursday's late match at 9 p.m. (1 p.m. EDT, 1900 GMT) in Nizhny Novgorod.
A look at Thursday's other matches:
DENMARK VS. AUSTRALIA
3 p.m. (8 a.m. EDT; 1300 GMT)
Australia, the decided underdog in a group that features three teams in the top 11 of the FIFA rankings, gets another tough matchup after dropping its opener to France.
A loss to Denmark — which is unbeaten in its last 16 international matches — would make it very difficult for the Socceroos to advance.
Still, Australia was heartened by its play in the loss to France, whose two goals both came about as a result of video technology.
"Coming away from the France game, it's refueled us and we can tango with the best," Australia defender Trent Sainsbury said.
Denmark will move on without starting midfielder William Kvist, who fractured two ribs and was sent home for treatment. He hopes to rejoin the team but is not expected to play again in the tournament no matter how far Denmark advances.
Goalkeeper Kasper Schmeichel was the star of Denmark's 1-0 victory over Peru, and scoring opportunities for both sides could be sparse with Australia coach Bert van Marwijk committed to a defensive style of play.
Van Marwijk hasn't said whether 38-year-old Tim Cahill will get on the field at Samara Arena. Cahill has scored 50 goals in 106 appearances and didn't play against France. With a goal, he would join four other players who have scored in four consecutive World Cups.
FRANCE VS. PERU
6 p.m. (11 a.m. EDT, 1600 GMT)
Tens of thousands of Peru fans have followed their team to the most remote city in this World Cup — Yekaterinburg, which is roughly 1,700 kilometers (1,056 miles) east of Moscow, a 25-hour drive that includes a pass over the Ural Mountains.
After cheering deliriously through Peru's first World Cup appearance in 36 years, the fans will have to wait at least a little longer to see a goal. Peru fired 17 shots at Schmeichel but couldn't convert during its opener against Denmark.
If Denmark were to get past Australia, a win by France would eliminate both Peru and the Australians from the competition.
The question for France and coach Didier Deschamps heading into the tournament was whether his young, talented team could play together effectively. France's uneven opener didn't provide a clear answer, and Deschamps could change his lineup or tactics, although he hasn't specified how.
Antoine Griezmann, the top scorer at the 2016 European Championship, remains the key to France's attack and will start, Deschamps said.
"He needs to do more, and he knows it," the coach said.
The big decision for Peru coach Ricardo Gareca will be whether to start the team's all-time leading scorer, Paolo Guerrero.