Rory Best began his final Rugby World Cup campaign with a try as Ireland accelerated away from Scotland en route to an opening win.
Ireland eased to a 27-3 Pool A win over Scotland in Yokohama on Sunday after a dominant first half in their Rugby World Cup opener.
With both sides looking for a strong start to surely avoid a quarter-final against New Zealand by topping the group, it was Joe Schmidt's top-ranked side who quickly accelerated out of sight.
James Ryan, Rory Best and Tadhg Furlong all crossed inside the opening 25 minutes and there was no way back for Scotland, who also had Hamish Watson carted off with a concerning knee injury before the break.
A scrappy second half was hampered by wet weather but Ireland claimed the bonus point with Andrew Conway's try shortly before the hour-mark.
It took Ireland just six minutes to take control, with Iain Henderson charging through a series of tackles to get his side to within touching distance of the try line, allowing Ryan to finally power over.
That lead was soon stretched further as Best drove Ireland forward at the back of a relentless maul following a lineout and, even with Ryan Wilson also able to get hands on the ball, twisted his body to touch down.
Greig Laidlaw dispatched a penalty to at least get Scotland on the scoreboard, but there was no stopping Ireland and they too easily found space following a scrum under the posts for Furlong to get the third.
Significant rainfall early in the second half added another dimension to the contest and slowed the attempted Scottish response.
Instead, Conway challenged for a high kick from the excellent Conor Murray and ultimately profited, with the wing found free on the right to dance inside one challenge and score.
Jack Carty, on for Johnny Sexton, added further gloss to the scoreline with a penalty, as even a yellow card for Tadhg Beirne - for failing to release - did not allow Scotland to belatedly reply.
Irish power too much
Scotland were largely able to match Ireland in terms of possession, but each and every error in the midfield was preyed upon. CJ Stander was particularly proficient at finding gaps and Schmidt's men were simply too strong for their opponents once within sight of the try line.
Sexton suffering?
Scotland assistant coach Matt Taylor had suggested they were going to "smash" Sexton, as they had in the Six Nations. In truth, they struggled to get close enough to the World Rugby Player of the Year, yet there was still concern for Ireland. The fly-half twice received treatment to his right thigh in the first half.
Murray was handed kicking duties before Carty later replaced Sexton.
What's next?
Ireland face a potential banana skin against hosts Japan next Saturday, while Scotland have to wait an extra two days to face Samoa in their second pool match.
