Johnny Sexton does not believe Ireland have peaked a year too early and says they have unfinished business at this year's Rugby World Cup.

The Ireland fly-half says they will go to Japan with a mixture of confidence and fear that will "bode well for us".

Ireland moved up to second in the world rankings after a superb 2018 but then had a lacklustre 2019 Six Nations.

Sexton says the hurt of disappointing World Cup exits in 2011 and 2015 will also spur the players on this autumn.

Fine margins

Under Joe Schmidt, Ireland enjoyed their greatest calendar year in 2018, winning the Grand Slam and a first series win in Australia since 1979.

They saved the best for last, recording a historic first victory over the All Blacks on home soil in November, but took a step backwards by finishing third in this year's Six Nations campaign and losing to both England and Wales.

"I don't think we have peaked," says Sexton.

"I didn't think we'd peaked when we won the Grand Slam and I didn't think we'd peaked when we beat the All Blacks either.

"It's amazing how opinions can change in the space of a couple of months.

"We beat the All Blacks and all the talk was 'nothing's going to stop us winning the World Cup' and then three or four games later, we're the worst team ever and people think we've peaked.

"We've got time together now to really work on things through the summer.

"We'll have some games beforehand to try and find our form and hopefully go to the World Cup knowing that, on our day, we can beat anyone but also have that fear that, on any day, we can lose to anyone as well.

"I think that's a good place to be. You always need that fear factor and that confidence as well.

"We've got a mixture of both and I think that'll bode well for us."

Sexton, the World Rugby Player of the Year, has won every trophy possible in his professional career, except for a World Cup.

The pain of the defeats by Wales in 2011 and Argentina in 2015 - when he was unable to play because of an injury picked up in the previous game against France - still haunt him.

Even this year's Champions Cup final loss to Saracens is something he says will stay with him, and with a World Cup on the line, plus the imminent departures of coach Schmidt and retiring captain Rory Best, Sexton will use past hurt to motivate him as Ireland seek to reach the semi-finals for the first time.

He said: "For everyone that's going it's unfinished business.

"We feel we maybe let it slip at the last World Cup and there's been some regrets from some of the other ones I was at too.

"In 2011 we had that quarter-final against Wales, knowing that if we won that - and we'd beaten Wales a few times - that we could have had France in the semi-final.

"Sitting and watching then [against Argentina in 2015] was very, very tough. You want to be out there with the guys, contributing with them and being in the dressing room afterwards was probably the lowest point, watching the lads suffering and not being part of it.

"So, there's always those regrets.

"That's why we'll be working extremely hard over the summer, to make sure we try and close those small margins in our favour and make sure we come away having done something special."

Ireland's Rugby World Cup fixtures

Sunday, 22 September - Ireland v Scotland

Saturday, 28 September - Japan v Ireland

Thursday, 3 October - Ireland v Russia

Saturday, 12 October - Ireland v Samoa