Johnny Sexton says Ireland can still contend for World Cup glory despite Saturday's shock defeat by hosts Japan.

Sexton is set to feature in Thursday's must-win Pool A game against Russia after missing the Shizuoka contest because of a thigh strain.

"It's up to us now to put in two big performances and hopefully get ourselves in to a quarter-final," said the British and Irish Lions fly-half.

"And we know that if we can get there we've got a chance.

"We've responded really well in terms of the other recent setbacks.

"Things went badly against England [in August's record 57-15 loss at Twickenham] but we beat Wales back to back and started with a bang against Scotland."

Sexton picked up his thigh knock in the opening 27-3 win over Scotland when he was also excused from the majority of Ireland's goalkicking duties.

He was forced to miss the Shizuoka shock as Jack Carty and Joey Carbery both struggled for control in the number-10 role amid Japan's domination of the contest.

While Ireland ought to ease past Russia without issue, Sexton is desperate to get back into action as soon as possible.

'Hopefully I can pay back the squad'

"I picked up that strain against Scotland, and I wasn't going to train fully Monday, Tuesday," added the 34-year-old.

"The preparation time was so short the guys made the decision for me to sit this one out.

"You want to play every game but hopefully I can pay back the squad this week and next week too."

Sexton added that Joe Schmidt's squad have to be grateful that Saturday's defeat didn't end their World Cup hopes.

"In the last two World Cups I've been involved in, we've not cruised through the group, but we've had everything go our way in the pool stages.

"And then we've had the day we had yesterday in the quarter-final. And we'd be going home today.

"So the great thing now is that we've got the rest of the pool to get things together.

"We know to a certain extent things are in our hands if we can win the last two games and score a number of tries that we can definitely qualify for the quarter-final."