Leinster’s seven-try defeat over Northampton at Franklin’s Gardens was the standout performance of the week-end, while Munster and Ulster scraped past Saracens and Harlequins respectively. Connacht will be seeking to right the wrongs from their loss away to Gloucester.

Leinster’s Garry Ringrose understands the factors at play when they face the Saints at the Aviva on Saturday.

“It’s part of the challenge. They will definitely want to react, a team of their quality. They won’t ever want to lose twice in a row.

They will be coming to the Aviva to win. It’s our job to do the same thing. We are playing at home this week, but the motivation is still to win, no matter what.

After 20 seasons of these one-two game combos, history has taught us to disregard the first of these weeks when contemplating the second. Leinster have proved the unpredictable nature of them at the first time of asking. Beaten 39-6 by a star-studded Stade Francais in Paris one week, a side playing under Mike Ruddock produced a 24-23 victory just five days later at Donnybrook in a game brought forward for the Christmas party crowd.

Leinster have rolled with the punches more than any of the other provinces in Europe in December, notably in the 04/05 and 05/06 seasons when they twice annihilated Bourgoin at Lansdowne Road and then struggled in France.

It’s hard to know which was more of a shock: winning 92-17 and then scraping a three-point win over there the first year, or the scenario 12 months later when they hit the Top 14 side for 53 points in Dublin and then lost by three at Stade Pierre Rajon.

Castres and, significantly given their return to the Aviva this Saturday, Northampton, have since overturned massive losses to the four-time champions by claiming unlikely victories against them second time around. Both were bolts to the boys in blue.

“We were referencing learning that the hard way (against Northampton) in 2013,” said Ringrose this week.

“It is kind of weird that you have to go back and play the same team again, because it rarely happens other than this time of year.”

Munster have found these legs of the European journey less volatile, but Castres caught them with a particularly painful sucker-punch just two seasons ago when edging a one-point game at Stade Pierre-Fabre after being demolished in Limerick.

Connacht made history in 2013 by winning in Toulouse, but paid for it with a 32-point spanking at the Sportsground. The daddy of all turnarounds in an Irish context occurred nine years earlier when Ulster embarrassed Leicester 33-0 and then lost 49-7 at Welford Road. There have been plenty of other examples this past two decades of sides winning away and then losing at home, or vice versa.

Northampton once conceded 40+ points away to Castres and then posted a 45-0 win at the Gardens a week later. Clermont posted a 42-point swing against Exeter three years ago. Newcastle Falcons once topped that, completing a 53-point swing against Toulouse.