Scotland opened their Rugby World Cup campaign with a heavy 27-3 defeat to Ireland as England swept Tonga aside.
Ireland, who enter the tournament as the world's number two-ranked team, delivered on their promise to hit form when it mattered most, fresh from a humbling 57-15 defeat to England just last month.
England meanwhile emerged 35-3 winners over Tonga despite a disjointed final half hour and some displeasure shown by coach Eddie Jones in the first half.
USA are England’s next opponents on Thursday while Ireland face hosts Japan two days later.
Ireland stunned Scotland with a bonus-point blitz to launch their Japanese World Cup quest in style.
James Ryan, Rory Best, Tadhg Furlong and Andrew Conway all crossed in Yokohama as Ireland made good on all their pre-tournament pledges.
Ireland's muscle-bound victory hands Joe Schmidt's men a fine chance to top Pool A and book a likely quarter-final battle with South Africa, following the Springboks' loss to New Zealand.
Ireland entered the tournament as the world's second-ranked team for the first time in history, but were also dogged by the spectre of their record 57-15 defeat by England at Twickenham just last month.
Head coach Schmidt's tournament plans had been heavily scrutinised, Rory Best's captaincy had been questioned, and Ireland were left to lament a second frustrating loss to England in the calendar year.
All boss Schmidt's plans came to fruition on the shores of Tokyo Bay however, with skipper Best leading from the front with a timeless, tub-thumping, try-scoring turn.
Ireland will move on to their next game feeling fully vindicated in their preparations, boasting a spring in their step and a zip in their play.
Having entered half-time with a 15-point advantage, England began to lose their way and the scrappy flow to the game played into Tonga's hands.
Even Manu Tuilagi dropped the ball as he was launched once again, but the lack of impetus was in part due to the vast number of changes made by Jones, including the arrival of Henry Slade at full-back.
A driving line-out bolstered by arriving backs arrowed over the whitewash in the 58th minute with Jamie George touching down and when play resumed Jones, whose side led 28-3, had used his entire bench.
It took until the 77th minute for England to secure the bonus point as Jonathan Joseph wriggled into space and sent Luke Cowan-Dickie sliding over, but it was the only highlight of a disjointed final half-hour as England emerged 35-3 winners.