Lionel Messi looks likely to be fully fit to face Brazil despite Luis Martinez's horror tackle on the Argentina captain, head coach Lionel Scaloni said.

Venezuela's Martinez was sent off for a crude lunge on the Paris Saint-Germain star in the Albiceleste's 3-1 World Cup qualifying win this week as Scaloni's men maintained their unbeaten streak.

There were concerns Messi would be a doubt for the clash in Sao Paulo against Brazil, who are six points clear at the top of the CONMEBOL standings after winning all seven of their qualifiers.

However, Scaloni was confident his talisman would be fit to start when speaking with the media on Saturday.

"Leo is okay," he said. "This afternoon, we'll train and focus on the pitch. Those who played against Venezuela didn't touch the ball yesterday [Friday].

"We'll know 100 per cent this afternoon. In principle, he's fine. It was a big scare, but that's how it stayed."

Scaloni expects an extremely difficult match against the side Argentina beat 1-0 in the final of the Copa America this year.

"Whoever plays, they're important opposition. In no case do we minimise the game," he said.

"They're coming off an incredibly positive streak and they're at the same level whoever plays, with players of quality in every position.

"These are opponents of enormous quality, of enormous attacking power. If you're not ready for that, you can suffer. If you don't think the opponent can hurt you, you're making a mistake.

"We know that it can happen at some point, but we also know what we have to do when we have the ball. We only have one way to play: go deep with the ball into the opposition half."