The two-time world champions, by virtue of the loss, are on the brink of early elimination from the tournament after picking only one point from two games. If they can beat the African outfit and Croatia avoid defeat by Iceland, Sampaoli's side will make it through to the last-16.
Iceland will retain their renowned sense of optimism as they take on already-qualified Croatia on Tuesday in a bid to claw their way out of World Cup Group D, coach Heimir Hallgrimsson said.
"The relationship with Sampaoli is totally normal, but if we feel uncomfortable, we will raise it".
"We know we're up against the wall but beating Croatia before gives us belief", said the midfielder.
"If we don't say what we think, we're going to get to the game with a lot of insecurities".
Franco Armani is tipped to replace Willy Caballero for the Nigeria clash after the Chelsea goalkeeper's blunder against Croatia, with Sampaoli also expected to ditch his three-match defence and return to a traditional back four.More news: Yemen forces retake Hodeida airport
Even if Iceland claim a first ever World Cup victory, Argentina could still progress on goal difference.
The 2014 runners-up are on the brink of an early World Cup exit in Russian Federation after a shock 3-0 defeat by Croatia.
"It's actually a disadvantage for us, it's unusual to say it but now we have players coming in who are still at the highest level, all motivated players who want to punch themselves into their first team", he said.
"I'm furious and very upset inside, because anyone who wore that shirt can't see it being trampled like that by a Croatian team that isn't Germany, that isn't Brazil, that isn't Holland or Spain".
"But there is a guilty party and the culprit is the president of the AFA".
Mascherano revealed that at the meeting with Sampaoli the coach had sought the views of his players.