Lionel Messi says he's unsure if this will be his last World Cup, but Argentina's fortunes in Russia could help him make a decision.

Argentina open their World Cup campaign against Iceland at the Spartak Stadium on Saturday, and it is widely expected that Messi will need to turn in a string of otherworldly performances in order for his country to lift the trophy for the third time.

At age 30, the belief is that Messi will be too old to take part in another World Cup, but the superstar wrote in a column for La Nacion that it all rests on how Argentina fare this time.

"They ask me if this will be my last World Cup and I don't know," he wrote. "I'm not thinking about that now. It will surely depend on how this month goes, on how we finish in the tournament."

Argentina manager Jorge Sampaoli said on Friday that he doesn't think that this will be Messi's final World Cup, and said the forward shouldn't feel he is under pressure to win it in Russia.

"[Messi] is very fit, he's very well prepared, he's really looking forward to World Cup, and he hopes to be able to achieve his dream," said Sampaoli at his prematch news conference. "He's a player who is very skilled, so I don't think he's under pressure. He shouldn't be under pressure in any case because he makes people very happy with his game.

"I don't think that this should be Messi's last World Cup. I don't think so. I think that his skills and the professional way he plays mean that he will be the one who decides until when he wants to play. He's a genius and he plays like a genius."

Argentina were stretched to the limit during World Cup qualifying, one that saw the Albiceleste burn through two managers before settling on Sampaoli.

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Sampaoli has had a rare stretch of extended time to mold his team, a period spanning 20 days and 34 training sessions.

"We're very excited about what we have seen," he said. "We're really looking forward to the beginning of this World Cup. I think that right now the team is very strong, very homogeneous, we have one common goal and we're very well prepared, we're ready.

"In these months we've had the possibility to strengthen things that we couldn't do before because we didn't have the time to train together. Tomorrow, I think that Argentina will be sure, will be convinced and will show we are really one of the strong teams in the world of football."

The Argentina manager will be experiencing the World Cup for the second time, having previously managed Chile at the 2014 World Cup. But managing his home country will be something special for the 58-year-old.

"The way I feel before this first game, well, I've got many different feelings, very strong feelings inside my heart," he said. "I think about my family, my friends, and everybody is telling me that the whole country is right behind us, supporting us, and they're hoping we make them happy."

Given the seriousness with which Argentina takes it's football, that can lead to immense pressure. Sampaoli said that's something he hopes his players will shift on to the opposition.

"Pressure is something that everybody feels, but we don't' let ourselves be put under pressure, because we need to simply play, enjoy every single game, and we have to forget this pressure, because otherwise we will not be able to perform as we want to perform," he said.

"That is what we have been doing. We don't want to be playing under pressure, we want them to be under pressure."

Sampaoli also went ahead and announced his starting lineup for the match, with Sergio Aguero starting in attack and the Juventus duo of Gonzalo Higuain and Paulo Dybala on the bench.