The biggest of World Cup shocks paid out for at least one prescient punter who correctly predicted Saudi Arabia would stun Lionel Messi's Argentina 2-1 in their opening match in Qatar on Tuesday.

British bookmakers Williams Hill said the customer won 1,600 pounds ($1,900) after betting 20 pounds on the shock scoreline at odds of 80-1.

"It's certainly been a good start to the World Cup for them," said Hill's spokesman Lee Phelps.

The punter could have got more by waiting, however, with half-time odds of 199-1 on Saudi Arabia winning after a dominant display by Argentina and Messi scoring from the penalty spot in the 10th minute.

"The shock loss has seen Argentina drift out to 15/2 to win the tournament, while they are out to 6/4 to win the group, having been odds-on at 2/5 prior to kick-off," said Phelps.