Saudi Arabia pulled off a stunning upset Tuesday, defeating highly favored Argentina, 2-1, in the group opener at Lusail Stadium in Lusail, Qatar.

Argentina, led by superstar forward Lionel Messi, entered the tournament as one of the tournament favorites, having not suffered a loss in 36 matches. Messi scored a penalty kick early in the contest but Saudi Arabia answered with two second-half goals to seal one of the biggest upsets in World Cup history.

Argentina, ranked No. 3 by FIFA, entered the match as -675 favorites over No. 51-ranked Saudi Arabia.

Saudi Arabia delivered a startling first-match defeat to championship contender Argentina.

Few underdogs have earned a more surprising win. In 1950, the United States defeated England, 1-0. In 1990, Cameroon earned a 1-0 win over Diego Maradona's Argentina squad. Senegal defeated defending champion France, 1-0, in 2002.

The victory was Saudi Arabia's fourth-ever win in the World Cup and their second since 1994.

Argentina dominated the first half. Messi scored in the 10th minute and Argentina had three goals disallowed. VAR showed that the offsides calls were accurate.

Saudi Arabia responded in the second half. Saleh Al-Shehri and Salem Al-Dawsari scored within four minutes and Argentina failed to equalize despite several chances.

In the other Group C match, Poland and Mexico finished 0-0. El Tri managed a draw after Mexican goalkeeper Memo Ochoa saved a penalty kick by superstar forward Robert Lewandowski.

Argentina faces Mexico on Saturday, while Saudi Arabia meets Poland.