Top-ranked Ireland have put aside their stuttering 2019 form with a clinical 27-3 victory over main pool rivals Scotland to open their Rugby World Cup campaign in convincing style in Yokohama.

Forwards James Ryan, Rory Best and Tadhg Furlong all scored tries in the first 25 minutes and winger Andrew Conway secured the bonus point with the fourth in the second half.

Scotland, who had a single Greig Laidlaw penalty to show for their efforts, tried to get their expansive running game going but were hamstrung by the Irish defence and slippery conditions from persistent drizzle.

There will be concerns that injury-prone flyhalf Johnny Sexton had given up the kicking duties early, and over head injuries to flanker Peter O’Mahony and centre Bundee Aki.

However, the Irish will move on confidently to their next group match against hosts Japan.