Ireland’s women have developed a reputation for doing things the hard way this past few years but few assignments have involved such a lengthy and unlikely stint in sporting purgatory as their second pool game at this Rugby World Cup.

Down by two converted tries at the break, Tom Tierney’s side were facing elimination from the semi-finals and the resultant ignominy before engineering a comeback that saw their game opponents worn down physically as the contest wore on.

The Japanese side rewarded the crowd with a long collective bow after the final whistle and they earned each roar and clap of the hands after giving the tournament hosts what was their second major scare in the space of just five days.

Ireland had made seven changes from the team that just about saw off Australia by two points on the tournament’s opening day last Wednesday but they were still expected to take care of business against the Asian side with some degree of comfort.

Victory was again a must given the hosts have still to face France and only one side is likely to come through Pool C and on to the semi-finals, but the first-half veered horribly off script in front of a packed crowd at UCD’s main venue.

A dodgy scrum and a plethora of errors, forced and unforced, had almost scuppered Ireland’s ambitions against the Wallaroos. Added to those self-inflicted wounds here was a dysfunctional lineout in the absence of regular locks Paula Fitzpatrick and Marie-Louise Reilly.

The scrum’s ills were especially hard to stomach against a ‘Sakura’ side that was light on size but heavy on intent and technical ability and they fashioned the game’s opening score from a penalty try when Ireland collapsed the scrum under their own posts.

There was close to a half an hour played by then but the problems deepened for Tom Tierney’s side against an opposition that enjoyed far more possession and territory and one marshalled intelligently by out-half Minori Yamamoto whose tactical kicking was excellent.

They had been camped in the Irish 22 more often than not by the time the second try was claimed, full-back Mayu Shimizu dotting down out wide after Irish eyes had been focused on keeping their forwards honest after a scrum five metres out.

The successful conversion left Japan 14-0 to the good and it was no surprise to see Ireland reappear for the second period with four new faces - Ailis Egan had already replaced Ciara O’Connor at tighthead right after the penalty try.

It got worse before it got better, outside-centre Katie Fitzhenry earning a deserved yellow card for a high tackle and, in truth, it was overdue from an Irish perspective after a number of similar hits on opposing players in the previous half.

Mairead Coyne, in particular, had been fortunate not to be sin-binned for one such infraction.

Still, Ireland with 14 players proved better than they had been until then with 15 and the first try came courtesy of wing Alison Miller who had started the move by blocking down a clearing kick back towards the halfway line.

Corner turned? Not quite.

Much improved though Ireland were, Japan continued to have their moments and it took a beast of a tackle from inside-centre Sene Naoupu inside Ireland’s own 22 to stem another growing tide. Minutes later and Naoupu was breaking the line at the far end.

It took a few more minutes and phases from there but the end result to that little chapter was a lineout, a maul and a push-over Paula Fitzpatrick try, converted again by out-half Nora Stapleton, which left it 14-apiece with fifteen minutes still to play.

By now, the tide was all green and Ireland finally got their noses in front with less than seven minutes to play when Stapleton chipped over a penalty after Japan had kept their line intact under growing pressure only thanks to a stray hand in a ruck.

It took all bar two seconds of the eighty scheduled minutes for the hosts to make it safe, Fitzpatrick just about burrowing over again, this time amid a pile of bodies, after an epic 34 phases, most of them inside the Japanese 22.

Stapleton’s conversion needed the help of a post before crawling over: a fitting end note and metaphor for the agonising manner in which the game had been won. The remedial work required between here and the French game will be considerable.

Ireland: M Coyne; H Tyrrell, K Fitzhenry, S Naoupu, A Miller; N Stapleton, N Cronin; L Peat, C Moloney, C O’Connor; C Cooney, S Spence; C Griffin, A Baxter, C Molloy. Replacements: A Egan for O’Connor (28); P Fitzpatrick for Baxter, L Lyons for Peat, R O’Reilly for Moloney and L Galvin for Coyne (all HT); J Deacon for Fitzhenry (53).

Japan: M Shmizu; E Hirano, I Nagata, R Kurogi, H Tsutsumi; M Yamamoto, M Tsukui; M Ebuchi, S Saito, S Minami; A Mimura, A Sakurai; Y Sue, S Suzuki, M Takano. Replacements: A Nakajima for Mimura (37); Y Noda for Tsukui (62); Misaki Suzuki for Ebuchi (64); Mizuho Suzuki for S Suzuki (75); A Suzuki for Tsutsumi (76).

Referee: I Tempest (England).