James Ryan admitted that memories of Ireland's 2019 World Cup defeat to Japan served as motivation for him and his team-mates as they battled to a 39-31 victory over the Brave Blossoms in Dublin.
Ireland survived some brilliant attacking Japanese play to gain revenge for that shock 2019 defeat.
While Ireland struck first and outscored the visitors by three tries to two to lead narrowly at the break, the scoreline did not tell the tale of a half which Japan dominated for long periods and played some breathless rugby.
The visitors regained the lead after a second superb assist from the boot of flyhalf Yu Tamura, but Ireland took control thereafter with Josh Van der Flier and Jacob Stockdale breaking the tit-for-tat scoring.
Japan began to tire and a more controlled Irish second half limited any further opportunities with Joey Carbery kicking Ireland into an eight-point lead they comfortably saw out.
Afterwards Ryan admitted that the previous meeting of the teams was never far from his mind.
"That game in 2019 was probably one of the hardest games I’ve ever played," he said.
"The way they play is such a fast, quick-tempo style of rugby so we knew when we saw this fixture that it was going to be a seriously tough day and that’s exactly what it was.
"That day in Shizuoka was a bit of motivation for us today and I’m delighted that we got the win in front of 3,000 fans. It’s the first time we’ve had fans in the Aviva for 18 months so it’s brilliant.
Japan looked fresher and more alert than Ireland at times, particularly in the first-half, and Ryan admitted that it took his side a while to settle into the game,
"They had two games under their belt and you could see that made a difference in the first-half," he said. "We were quite slow to start.
"But I think that was a positive as well - we didn’t panic. In the first half we were able to have some good conversations and put in a really good 40 minutes in the second-half.
"I’m delighted for the lads. [It was] Gav Coombes’ first cap as well, a special day for him so it was a good day."
James Ryan gives his reaction to Ireland's 39-31 victory over Japan and his side's performance. Ryan is also asked about his absence from the Lions squad. #IREvJPN #RTERugby pic.twitter.com/RGf0CHusbQ— RTÉ Rugby (@RTErugby) July 3, 2021
Ryan was also asked about his Lions summer tour disappointment.
Andy Farrell had revealed that Warren Gatland enquired about the possibility of Ryan replacing the injured Alun Wyn Jones in the Lions squad but that an adductor injury for the Leinster lock scuppered his chances.
Since then however Ryan recovered sufficiently to captain Ireland against Japan and was not in a forthcoming mood when addressing the Lions question.
"I've been carrying a few niggles but credit to the physios who were able to get me back in time for this.
"I was delighted to be able to play today and to lead out my country is always a huge honour. We’re delighted with that result and we look forward to next week."