Three European sides were in action on Saturday: Poland, France and Denmark. But the most significant game of the day was Argentina v Mexico with the losing side in all likelihood out of the competition, so both Latin American football powerhouses were fighting for victory in Qatar on Saturday night.
Tunisia 0—1 Australia
Australia run out 1-0 winners, thanks to a Mitchell Duke header from a cross by Craig Goodwin in the first half.
The victory puts Australia back within a shouting chance of qualification from Group D, following the Socceroos' 1-4 routing by France in their opening match.
Tunisia however remain rooted to the bottom of the table on one point, after their opening goalless draw against Denmark. This despite having lost just one of their last 10 matches going into the tournament.
Tunisia and Australia met for just the third time in history, with the last match a 2-0 Tunisia victory in the 2005 Confederations Cup.
Poland 2—0 Saudi Arabia
Robert Lewandowski scored his first World Cup goal in a 2-0 victory that puts Poland on top of Group C with four points.
Piotr Zielinski gave Poland a late first-half lead, before goalkeeper Wojciech Szczesny made an amazing double save when Saudi Arabia were awarded a penalty.
First he plunged to his right to keep out Salem Al Dawsari's penalty, before leaping to his left to deflect Mohammed Al Burayk's follow-up over the bar. Already people are talking about the save of the tournament.
With 10 minutes to go, Lewandowski pounced on a defensive error, slotting home with his left foot -- finally breaking his scoring duck after four previous World Cup matches without a goal.
Saudi Arabia come down to earth after pulling offf an incredible upset to beat Argentina 2-1 in their first match. They have now lost 10 of their last 11 World Cup matches against European teams, including an 8-0 loss to Germany in 2002.
France 2—1 Denmark
The 2-1 win for the defending world champions against Denmark means France qualify for the last 16.
After a tight, goalless first half, the match came to life on the hour when Kylian Mbappe slotted home to give France the lead.
Minutes later, Denmark's Andreas Christensen headed an equaliser from a corner.
The goals totally opened up the match, with a flood of chances at both ends before Mbappe got on the end of a pinpoint cross from Antoine Griezmann to score his and France's second and decisive goal with just minutes remaining.
France overcame a slew of injuries -- including the loss of striker and Ballon d’Or winner Karim Benzema with a thigh injury on the eve of the tournament -- for an easy 4-1 defeat of Australia in their opening match.
The victory over Australia made France the first reigning champion to win their opening match of a World Cup finals since Brazil in 2006, but only four champions have won their opening two matches of a World Cup campaign.
France have also succeeded in becoming the first team since Spain in 2010 to win six consecutive World Cup matches.
Denmark had drawn their previous three matches including a 0-0 tie against Tunisia in their opening game.
Argentina 2—0 Mexico
Leo Messi breaks the deadlock in a tense match with a firm strike from just outside the penalty area just after the hour.
Enzo Fernandez of Benfica doubles Argentina's lead with a sublime shot late in the game, to secure the 2-0 victory.
Messi's goal was his eighth in a World Cup finals, putting him level with a certain Diego Maradona.
Argentina have only failed to advance out of the group stage twice in the last 60 years, in 1962 and 2002.
The odds were in Argentina's favour: they had beaten Mexico in their last 10 meetings dating to the 2004 Copa America, and they won all three of their previous World Cup matches against Mexico at the World Cup, in 1930, 2006 and 2010.
Mexico have now failed to score in their last four World Cup matches dating back to the group stage in Russia 2018, and came into the match with Argentina following a 0-0 draw in their opening match against Poland in Qatar.
Poland now lead the group on 4 points, followed by Argentina and Saudi Arabia on 3, and Mexico in last place with one point.
What happened at the World Cup on Friday?
England missed the chance to advance to the last 16 by securing just a lacklustre 0-0 draw against USA.
Colombian captain Énner Valencia has become the top scorer at this World Cup with his third goal.
Hosts Qatar have crashed out without scoring a single goal, from a tournament they spent an estimated €200 billion preparing for.
Iran secured a stunning 2-0 win against Wales with both goals coming in injury time after the Welsh keeper had been red-carded.
What are the key talking points so far?
Some high profile teams have been humbled: Saudi Arabia beat Argentina 1-2, while Japan beat Germany 1-2, and England were lucky to hold on with a 0-0 draw against USA.
Records have fallen: Portuguese star Cristiano Ronaldo made history as the first male player to score at five World Cups.
Drama on the pitch: German players held their hands over their mouths in a silent protest before kick-off of their first game, while Iranian players refused to sing their national anthem in the first game -- but were back to singing in the second game after a well-known player who didn't make the squad was arrested in Tehran, sending a clear signal to the players in Doha.
Drama off the pitch: European countries have lodged complaints against FIFA's ban on team captains wearing anti-discrimination armbands at the games.