Ireland began to put their World Cup back on track after the shock loss to Japan but it took them over an hour to secure a bonus point and strengthen their quarter-final chances in an unconvincing 35-0 win over a stubborn Russia on Thursday.

Ireland just need to beat Samoa to reach the last eight and can finish top of the pool if Japan slip up but the fact Joe Schmidt's side struggled to put away such a limited team will do little for fans' waning hopes of reaching a first semi-final.

Only a commanding win would have sufficed with the shock in Shizuoka still reverberating around the tournament and it looked on the cards when Rob Kearney, who scored in the 62-12 trashing of Russia in the 2011 World Cup, touched down after 90 seconds.

Ireland's players had suggested short, sharp passes could best counter the slippery, humid conditions under the roof at the Kobe Misaki Stadium and it was just that tactic that helped Kearney find a gap and sprint through.

Johnny Sexton, who was not risked against Japan due to a thigh injury, appeared to have Ireland rushing towards the bonus point when his textbook 13th-minute dink through was carried over by flanker Peter O'Mahony for just his second try in 62 tests.

Yet Russia, who belied their lowly standing by giving Japan a fright and were mainly outdone by a short turnaround against Samoa, remained competitive with Ramil Gaisin's smart kicking helping to keep Ireland at bay for another 20 minutes.

While some basic errors cost the world's 20th-ranked side early on, Ireland could only manage a solitary Rhys Ruddock try when Bogdan Fedotko and Andrey Ostrikov were yellow carded either side of halftime for The Bears.

Sexton, captaining his country for the first time, kicked flawlessly before being replaced at halftime and Ireland's focus left with him in an error-strewn third quarter in which the Russian pack bossed the far more experienced opposing eight.

Though cooler in the stadium than when Samoa and Scotland struggled to hold onto the ball on Monday, the greasy surface played a part in Ireland's scrappiness before Andrew Conway was put through for his second try of the tournament on 62 minutes.

Centre Garry Ringrose added his second try in as many games to give the scoreline a slightly less flattering look than the Russians' efforts possibly deserved.

The win puts Ireland on 11 points, while unbeaten Japan (nine) face Samoa (five) on Saturday. Scotland also have five points and play Russia next Wednesday in Shizuoka before ending the pool phase against the tournament hosts in Yokohama on Oct. 13.