Lautaro Martinez put Argentina's stunning 2-1 defeat to Saudi Arabia in their World Cup Group C opener on Tuesday down to their own "mistakes".

Lionel Messi put La Albiceleste ahead early on from the penalty spot at Lusail Stadium, but two goals in the space of five second-half minutes from Saleh Al Shehri and Salem Al Dawsari completed one of the biggest shocks in World Cup history.

Martinez, who had two efforts ruled out for offside with the score at 1-0, lamented his side's sloppiness and says their focus needs to turn immediately to their two remaining Group C games against Mexico and Poland.

"We lost the game due to our mistakes more than anything in the second half," he said. "In the first half we had to score more than one goal, but this is the World Cup.

"Now to rest and think about what is coming. It's two big games now. Mexico and Poland are going to make difficult rivals, as it was today too. 

"In the second half we made mistakes; we have to correct that for what is to come.

"The defeat hurts a lot. We wanted to start by winning, but it's over. We need to think about the games that are coming."

The defeat was Argentina's first since July 2019, when they lost 2-0 to Brazil, ending a run of 36 matches unbeaten.

The result saw Lionel Scaloni's men lose a World Cup match after scoring the first goal for the first time since 1958 against Germany, while it was the first time they lost after leading at half-time since the 1930 final against Uruguay.