Stand-in Ireland captain James Ryan hopes to shake off the lingering injury issues that have affected him in recent months once he completes his international duties next weekend.

The Leinster lock was a doubt for Saturday afternoon's hard-fought 39-31 Test victory over Japan because of an adductor problem that seemed to scupper a place of linking up with the British and Irish Lions in South Africa.

However, Ryan was passed fit and led Ireland out in front of 3,000 supporters at the Aviva Stadium as regular skipper Johnny Sexton has been rested for the summer assignments alongside Keith Earls and Cian Healy.

Ireland now turn their attention to a clash against the United States next Saturday, which will mark the end of a long and at times frustrating campaign for Ryan, who is determined to use the off-season to his advantage.

"The last couple of weeks I was managed quite a lot, a credit to the physios for getting me back, it was a huge honour to lead the boys," Ryan said.

"At times throughout the season I've had niggles and little breaks in the game, I probably haven't been able to put games and weeks together the way I would have liked.

"After these next couple of games it will be a good window for myself to work on little niggles so I can commit fully physically into next season and beyond.

"But leading the boys was a huge honour and we're really happy with the result."

With seven of their contingent on Lions duty, plus the senior trio of Sexton, Earls and Healy absent, there was a fresh look to Ireland for their first meeting against the Brave Blossoms since the 2019 World Cup pool stages.

On that occasion, the tournament hosts sprung a major surprise in Shizuoka but despite an error-strewn first-half showing in Dublin, Ireland went in at the interval 19-17 ahead before a better outing after the break.

Chris Farrell, Stuart McCloskey, Finlay Bealham, Josh Van Der Flier and Jacob Stockdale touched down while Joey Carbery added the extras to four tries before two late penalties ultimately took the wind out of Japan's sails.

"The game in 2019 was one of the toughest games I've played," Ryan added. "Thankfully it wasn't as humid in Dublin as it was in Shizuoka!

"When you saw this game on the fixture list you knew it was going to be a very tough day and that's exactly what it was.

"Their attack is their point of difference, really, their organisation, their knowhow, so it was very, very tough out there.

"We were certainly blowing pretty heavy, particularly in the first half, but I thought it was a great effort defensively at times.

"We did concede 31 points but we stuck in there, I thought the guys that came off the bench had a great impact, a great energy which was big for us in that last quarter. A good learning for us all-round.

"It's the first time we've had our fans in 18 months in the Aviva. Even 3,000 makes a massive difference for us."