So much was expected of Samoa, which was the bettors' favourite against England and stacked with players from the NRL final. But they didn't have a warmup match, were vastly under-prepared, and lacked any kind of cohesion. All they generated was an intercept try by centre Izack Tago.
To make matters worse, loose forward Braden Hamlin-Uele (calf), utility back Tyrone May (dislocated hip) and winger Hamiso Tabuai-Fidow (ankle) were unlikely to take any further part in the World Cup.
Samoa should improve through the tournament and will need to if it meets Tonga in the quarterfinals, while England can look forward to a probable last-eight meeting with Papua New Guinea.
Anticipating a tough battle up front, England coach Shaun Wane included four forwards on the bench and the tactic paid off as Samoa was steamrolled.
Wane handed competitive debuts to NRL-based trio Dom Young, Herbie Farnworth and Victor Radley and all impressed.
Winger Tommy Makinson led England's spree with a personal haul of 24 points, scoring one try and adding 10 goals from 12 attempts.
Halfbacks Jack Welsby and George Williams hit the ground running. Skipper Sam Tomkins put Williams through a gap and Welsby was in support to touch down the first try in the 18th minute.
Welsby then provided cut-out passes for winger Young to go over twice in five minutes.
Tago picked off Welsby to make it 18-6 at halftime but the fightback was snuffed out eight minutes into the second half when center Kallum Watkins took Mike McMeeken's pass to go in for England's fourth try.
After Samoa scrumhalf Anthony Milford was sinbinned for a late tackle on Tomkins, England piled on with tries to Farnworth, Elliott Whitehead twice, Makinson, Williams and prop Tom Burgess.
"We always knew we were a bit underdone but didn't expect a result like that," Samoa coach Matt Parish said. "That's the first game and it's the result of the last game that counts. We can put in a lot better performance than that."
The Kangaroos found themselves four points behind within four minutes after Fiji centre Semi Valemei flopped on a short kick behind the line.
Australia had to fight for an 18-4 halftime advantage but wrested control after the interval with winger Josh Addo-Carr completing a try double and Valentine Holmes completing a perfect set of seven conversions.
Fiji, a semifinalist in the last three World Cups, was more than a match for Australia in terms of brute strength, but moments of sloppiness were ruthlessly exploited.
Jeremiah Nanai scored on debut, Latrell Mitchell served up a try for Angus Crichton, Mitchell was repaid by a one-hand pass from Cameron Munster, hooker Harry Grant steamed over in a move he kick-started himself with a 40-20, and captain James Tedesco jinked through a tiring Fiji backline.
Fiji had the last say, fullback Sunia Turuva's try prompting one of the biggest cheers from the Headingley crowd of 13,366.