
Title favourites New Zealand and two-time winners Australia scored impressive victories as they beat Italy and Japan 76-14 and 91-3 respectively.
However, holders England struggled against the United States, beating their transatlantic cousins by "only" 28-10.
In Lyon, Australia scored their second-best winning margin at the competition as they trounced Japan in a Pool B game. The 88-point margin was bettered only by their 142-0 victory against Namibia in 2003.
Japan managed to restrict the damage to just 23-3 at half-time, but in the second half the Wallabies ran riot and scored ten tries.
Rocky Elsom established a new record in the game with the fastest- ever hat-trick by a forward in the competition's history. There were 17 minutes between his first and third try.
Elsom's 15-points tally was beaten only by their captain Stirling Mortlock, who converted seven tries and kicked two penalties for a total of 20 points.
Australian try scorer George Smith, said that they had expected the game to be difficult in the beginning. "We always knew the Japanese were going to come out pretty tough at the start and they did. But there is obviously more we can work on, but the boys were really disciplined in their game."
In the earlier Pool C game played in Marseille, New Zealand ran in 11 tries for an easy 76-14 victory against Italy.
Dan Carter top-scored for the All Blacks with seven conversations and one penalty for a personal tally of 17 points, two more than Doug Howlett, who ran in three tries.
The three tries took Howlett's international career tally to 46 tries, equalling Christian Cullen's All Blacks record.
There was never any chance of an upset and it took New Zealand just two minutes to get onto the score sheet when captain Richie McCaw went over for the first try of the day.
McCaw said after the match that he had been pleased with his side's performance. "Of course we are very happy. We were looking forward to playing this game for a long time. And we played very well in the first 20 minutes. We capitalised on every opportunity we had."
The New Zealand coach Graham Henry also highlighted the first 20 minutes. "I am very pleased. We played some good rugby in the first 20 minutes despite the heat. We have no injuries, so it's ideal."
In the day's final match, played at Lens, the game Americans made the 80 minutes a tough slog for England, which was playing without the hero of its 2003 World Cup championship, Jonny Wilkinson.
Jason Robinson (in the 34th minute), Olly Barkley (40th minutes) and Tom Rees (47th minute) scored tries within 13 minutes, with Barkley converting two of them.
But the holders made little of their overwhelming territorial advantage. And when Atekitonga Moeakiola muscled over a try in the 74th minute, it was more than deserved.
England will have to push up their game several notches to have a chance of rivalling South Africa for the Pool A top spot, or to hold off the rugged Samoans for a spot in the quarterfinals.
Four matches are scheduled on Sunday, as South Africa meets Samoa in another Pool A match, Wales faces off against Canada in Pool B, Scotland and Portugal meet in Pool C and Ireland play against Namibia in Pool D.
On Friday Argentina stunned hosts France 17-12 in the opening match of the September 7 to October 20 tournament, which will be held in various French cities, as well as Cardiff in Wales and Edinburgh in Scotland.
DPA