Lionel Messi scored a hat-trick to become the World Cup's joint-top all-time scorer as reigning champions Argentina began their defence with a statement victory over Algeria.
Making his 200th appearance for his country, Messi scored his first treble at a World Cup just a week shy of his 39th birthday.
And it created a piece of history, as the eight-time Ballon d'Or winner took his World Cup finals goal tally to 16 - moving him level with Germany's Miroslav Klose as the all-time leading scorer in the competition's history.
His first came when he collected the ball from Inter Miami team-mate Rodrigo De Paul before bending a strike past Luca Zidane - the son of France legend Zinedine Zidane - on his 27th World Cup appearance.
Messi and Argentina's second came from close range on the hour mark when the Inter Miami man pounced on a mistake from Zidane, before he sealed a first World Cup hat-trick in the 76th minute when he arrowed home a thunderous strike from the edge of the area.
Kylian Mbappe picked up where he left off in the World Cup by scoring twice as France beat Senegal in New Jersey.
The Real Madrid star striker scored a hat-trick in the final in Qatar four years ago and started with a brace at this tournament.
In doing so he became France's all-time leading goalscorer with 58 goals for his country - one clear of former record holder Olivier Giroud.
Mbappe broke Senegal's resistance in the second half with a low strike before rifling home a sensational long-range effort deep into stoppage time.
Bradley Barcola had earlier put France 2-0 up before Ibrahim Mbaye pulled one back, but Mbappe's second of the game ended Senegal's hopes of a comeback.
Anything Mbappe can do, Erling Haaland can do too as the striker netted twice on his World Cup debut as Norway overcame a spirited Iraq in their opening Group I game at Boston Stadium.
The 25-year-old took his tally to 57 goals in 51 appearances for his country as they made their World Cup return after 28 years, though he was denied the 55th hat-trick in tournament history by Jalal Hassan's fine block late on.
Making their first appearance on the biggest stage in 40 years, Iraq more than held their own in the opening stages but the deadlock was broken just 58 seconds after the first-half hydration break when the overlapping David Moller Wolfe swung in an inviting low cross from the left which Haaland slid home at the far post.
Iraq deservedly levelled on 39 minutes as Amir Al-Ammari's cross which was met by a powerful downward header inside the upright by Aymen Hussein, who sealed his country's place at the World Cup with the winner in the intercontinental play-off final against Bolivia in March.
In the final game of the day Austria beat Jordan 1-0 thanks to a goal from Romano Schmid.
It was a stunning strike that appeared to come from nothing. Schmid cut inside and curled a shot beautifully past Yazeed Abulaila in the Jordan goal
But Jordan pulled a goal back through Ali Olwan before Austria retook the lead and take all three points thanks to a Yazan Al Arab own goal and then Marko Arnautovic made it 3-1 from the penalty spot deep into stoppage time.
