Earlier, Argentina changed goalkeepers for their final World Cup Group D match against Nigeria on Tuesday, with Franco Armani starting in place of the error-prone Willy Caballero and striker Gonzalo Higuain also getting his first start.
Lovren has revealed that the reserve players have twice beaten the first team in Croatia practice matches at their training base.
However, global success with Argentina has eluded him over his career, which has been highlighted in Russian Federation as they face a humiliating early exit. They might be able to snatch a win here, but don't be surprised if Peru come away from the tournament having bagged at least a point in their final game.
Messi led Argentina to the World Cup final four years ago and consecutive Copa America finals in the following two years, but all three ended in defeat.
Sergio Aguero is set to be axed by Argentina for their must-win group game against Nigeria on Tuesday. However, the name of Lionel Messi remains absent.
"Tomorrow Argentina will start its World Cup", he told reporters on Monday.
In Group D, 2014 runners-up Argentina are on the brink of elimination and must win against Nigeria.More news: Bulldog from Minnesota wins World's Ugliest Dog title
"Leo is fine", said Hebei China Fortune midfielder Javier Mascherano, who was Messi's teammate at Barca for eight years.
"I was not surprised he struggled, in what was a disastrous defeat for us".
By his own high standards, Messi has been way below his usual level in Argentina's first two matches.
Eight teams will play for glory in the Soccer World Cup today.
His 31st birthday on Sunday only served to highlight how time is running out for Messi to win a major global tournament.
In their hour of need, Argentina need Messi's best once more.
A win against Argentina will guarantee Nigeria a place in the second round.
He is one of various animals testing their psychic credentials at the World Cup, including hippos Milya and Glyasik in Kaliningrad, Spartak the lemur in Yekaterinburg and Harry the otter in Sochi.