No team has more material to work with when it comes to figuring out what went wrong in the knockout stages of Rugby World Cups than Ireland.There have been so many disappointments that if Andy Farrell's Six Nations winners are able to learn their lessons from previous Webb Ellis flops then they will finish top of the class.They remain the only top tier nation not to have qualified for the semi-finals from nine attempts.Johnny Sexton won't have any memories of the 1987 and 1991 tournaments, but as a rugby-mad ten-year-old in 1995, it's highly likely that he can recall flashes of brilliance from Jonah Lomu or even Simon Geoghegan.The sight of a futile 13-man lineout in Lens stands out from 1999, while the 2003 loss to France is probably buried somewhere in the back of the mind.Sexton was coming through the Leinster ranks when the 2007 debacle occurred but for the last three renewals he has had a front-row seat.Coming into the 2011 tournament in New Zealand, Sexton was first-choice out-half before losing his spot to Ronan O'Gara.
He came on as a second-half replacement as Wales pulled away in the quarter-final.Ireland's 2015 RWC came to an end against Argentina, with Sexton missing the quarter-final with a groin injury suffered in the win over France.Entering the World Cup year of 2019 as the number one ranked team, Joe Schmidt's men, with Sexton out of the matchday squad, suffered a stunning loss to hosts Japan in the pool stages before getting steam-rolled by New Zealand in the quarters.Sexton could do little as the All Blacks ran in seven tries.At that stage, few would have predicted that Sexton would be around four years later to try to makes amends but the two-times Lions tourist is still the clear leader, in title