Defeat to outsiders Saudi Arabia in their opening Group C match in Qatar had left Argentina on the brink, knowing another loss would spell the end of their tournament chances.

But the Albiceleste just edged a disjointed and tetchy affair against their fellow Latin Americans at the Lusail stadium in Doha.

And who else but the mercurial Messi should be the hero, firing home a low shot from 20 yards on 64 minutes, before Enzo Fernandez added a thunderbolt second goal for Argentina three minutes from time.

"The first game cost us," said Messi. "We knew that we had to win today, that another World Cup was starting for us and we knew how to do it.

"It was a tough game to pick ourselves up for because Mexico play well.

"We played the first half with intensity but the second half we relaxed and became ourselves again."

Messi's goal meant he tied the late Diego Maradona on eight goals and 21 appearances at the World Cup for Argentina.

It came a day after Argentines marked the second anniversary of Maradona's death.

"I always dreamed as a kid of wearing this jersey," Fernandez said.

"Today I achieved the dream of scoring in a World Cup," the 21-year-old Benfica player added.

The goals were two rare moments of quality in an often poor and tense encounter where the occasion seemed to get to everyone, except seven-time Ballon d'Or winner Messi.

But Argentina still need to win their final group match against Poland to guarantee a place in the knock-out stages.

"We cannot let up now. Every game is a final now, we cannot make any mistakes," said Messi.