The second-lowest ranked team in the World Cup has stunned the football world with one of the biggest upsets in the tournament’s history against Lionel Messi-led Argentina.

Saudi Arabia pulled off what SBS commentator Mark Tyler said was “unthinkable” by defeating a team that is among the contenders to win the cup.

The 2-1 result broke Argentina’s amazing 36-match undefeated run and stopped it from matching the previous international record of 37 games unbeaten held by Italy.

Messi said his team was feeling very “bitter” about the “tough blow” from a team ranked 48 places lower, but he said Argentina would regroup.

Saudi Arabia celebrates after scoring against Argentina. Photo: Getty

The thrilling match was played out in front of a frenzied crowd of 88,012 in Qatar.

At one-nil down after a Messi penalty in the tenth minute, the gulf nation threw caution to the wind in the second half.

Saleh Al-Shehri squeezed in a low shot in the 48th minute.

Then Salem Al-Dawsari curled in a scorching strike from the edge of the penalty area in the 53rd minute to leave Argentina and Messi looking utterly shell-shocked in the group C opener.

Lionel Messi says Argentina has been dealt a tough blow in its opening match. Photo: Getty

Despite plenty of possession after that, Argentina was unable to penetrate Saudi Arabia, which was competing in its sixth World Cup but had never previously won an opening game.

The entire game was played in an extraordinary atmosphere at the Lusail Stadium, with Argentina’s traditionally massive and raucous following matched by the thousands of Saudis who had come over the border to cheer on their team.

“Our team fulfils our dreams!” and “Where is Messi? We beat him!”, the green-clad Saudis chanted over and over, on their feet and greeting every clearance from their defence with a deafening roar.

Socceroos v France

Socceroo Mathew Leckie and Theo Hernandez of France battle for the ball. Photo: Getty

The seismic upset would have given hope to Australia’s Socceroos as they played their first match on Wednesday morning (AEDT).

But despite an exciting early goal by Craig Goodwin, Australia lost the match to a dominant France, going down 4-1.

Half-a-dozen Australian footballers were making their World Cup finals debuts in Qatar.

Only captain Mat Ryan, Mathew Leckie, Aaron Mooy, Jackson Irvine and Aziz Behich have previously featured in soccer’s showpiece tournament.

The match was the first of Australia’s group games at the cup with fixtures against Tunisia (Saturday, 2100 AEDT) and Denmark (December 1, 0200 AEDT) to follow.

Tweet from @Socceroos

Ronaldo gone

In other soccer news, superstar Cristiano Ronaldo will leave Manchester United immediately after his explosive interview criticising the club.

United issued a statement on Tuesday evening (local time) announcing they had reached a mutual agreement with the player to terminate his contract.

The development comes a week after Ronaldo unsettled the club in an outspoken TV interview.

The Portuguese issued his own statement which read: “Following conversations with Manchester United we have mutually agreed to end our contract early.

“I love Manchester United and I love the fans, that will never ever change. However, it feels like the right time for me to seek a new challenge.

“I wish the team every success for the remainder of the season and for the future.”

The development means Ronaldo is now free to negotiate with other clubs.

Ronaldo’s relationship with the club had appeared to become strained during the early part of the season and problems were brought to a head by last week’s interview with TV presenter and journalist Piers Morgan.

Among his comments in the programme were claims that he felt “betrayed” by United and that he had no respect for ten Hag.

He also said that he felt people at the club were trying to force him out and that United showed a lack of empathy when his daughter was in hospital ill.

There were also wider complaints about the standard of facilities at the club as well as criticism of the owners.

When United responded by appointing lawyers to consider potential action for alleged breach of contract, it became clear a parting of the ways was likely.

-with AAP