Hosts Qatar are at risk of an early elimination from Group A following their opening 2-0 loss to Ecuador, who are joined in the knockout berths by the Netherlands after their 2-0 success over Senegal.
England have set the pace at the top of Group B after thumping Iran 6-2, while Gareth Bale was his nation's hero once again as Wales rescued a 1-1 draw versus the USA.
Group C produced one of the early shocks as Saudi Arabia came from behind to beat Argentina 2-1 and end the Copa American winners' 36-game unbeaten run, while Mexico and Poland drew 0-0 in the other fixture.
Reigning champions France kicked off Group D with a thumping 4-1 win over Australia, as Denmark and Tunisia played out one of the other goalless draws in matchweek one.
Germany's quest for glory in Group E began disastrously with a shock 2-1 loss to Japan, but there was no such giant killing in Spain's meeting with Costa Rica, as La Roja ran out emphatic 7-0 winners.
Belgium survived a wave of Canada pressure to prevail 1-0 in their opening Group F game, as Morocco's showdown with Canada ended goalless.
Closing out the first gameweek, Brazil stormed to the top of Group G after beating Serbia 2-0, while Switzerland edged a close contest with Cameroon 1-0.
Finally, Portugal survived a late scare to beat Ghana 3-2 in Group H, while South Korea and Uruguay played out the fourth 0-0 draw of the week.
Here, Sports Mole selects its Team of the Week for the first round of World Cup fixtures.
DEFENCE
While Japan's substitute attackers rightly collected the plaudits against Germany, alongside coach Hajime Moriyasu, the efforts of goalkeeper Shuichi Gonda were also invaluable, as the 33-year-old made eight saves and two punches in a famous win.
Similarly, Ecuador's hero of the hour against Qatar may have been record-breaking Enner Valencia, but right-back Angelo Preciado certainly played his part, providing the cross for Valencia to double his side's lead and also making five tackles and two interceptions in an assured display.
Saudi Arabia's shock win over Argentina will be spoken about for years to come, and the heroic efforts of Hassan Al-Tambakti at the back characterized their performance, with the centre-back winning all three of his ground duels, making three clearances and producing a strong header off the line in a display that rightly earned him plenty of plaudits.
Spectacular attacking displays were not on show during Belgium's success over Canada, but veteran centre-back Toby Alderweireld showed that there is plenty of life left in his 33-year-old legs, providing the long ball for Michy Batshuayi to slot home while also making a mammoth 12 clearances to keep the Canucks at bay.
Fellow veteran Jordi Alba may have lost his place in the Barcelona XI this season, but the left-back retains the faith of Spain boss Luis Enrique and repaid that trust against Costa Rica, winning a controversial penalty, setting up Marco Asensio with a pinpoint low cross and completing 93% of his passes for the dominant Roja.
MIDFIELD
All eyes were on Jude Bellingham when England took to the field against Iran, and despite some early nervous moments, the Borussia Dortmund teenager did what he does best, looping a header over Hossein Hosseini for the opening goal and completing 96% of his passes in an exemplary performance.
Bellingham was not the only goalscoring midfielder to use his head in matchweek one, as France lynchpin Adrien Rabiot drew Les Bleus level against Australia before winning the ball back high up the field and setting up Olivier Giroud for his side's second, and he also produced five tackles and a 90% pass accuracy for the champions.
While the likes of Bruno Fernandes and Casemiro deserve mentions, there was no ignoring the history-making Gavi, whose stunning outside-of-the-boot goal versus Costa Rica made him Spain's youngest-ever World Cup goalscorer and the youngest at the tournament since Pele in 1958, and he also flicked a deflected ball into the box for Dani Olmo to score in a display well beyond his tender 18 years.
ATTACK
If one needed any more proof that Bukayo Saka had banished the demons of his penalty miss at Euro 2020, the Arsenal starlet certainly showed it against Iran, scoring a stunning half-volley before making it a brace for himself on his World Cup debut by cutting inside and sending a deflected effort into the bottom corner.
The likes of Enner Valencia and Mehdi Taremi were difficult to leave out after their respective braces, but Olivier Giroud's tap-in and bullet header against Australia took him up to 51 goals in France colours - the joint-most of any men's player alongside Thierry Henry - and one would not put it past the 36-year-old to break that record before the group stage is over.
Despite struggling for goals at Tottenham Hotspur, putting on the Selecao strip evoked a fire within Richarlison, whose side were struggling to break down a dogged Serbia defence before he was in the right place at the right time to tap home, and nothing else needs to be said about his spectacular bicycle kick to rubber-stamp an opening win for the favourites.
SPORTS MOLE'S WORLD CUP TEAM OF THE WEEK
Sports Mole's World Cup Team of the Week (4-3-3): Gonda; Preciado, Al-Tambakti, Alderweireld, Alba; Bellingham, Rabiot, Gavi; Saka, Giroud, Richarlison