A new-look Ireland ground out a 36-20 victory over an energetic Japan in the Nations Championship on Saturday to stretch their win streak to six, but coach Andy Farrell admitted the scoreline "flattered" his side.
Five Irish players shared the try-scoring spoils on neutral territory at Newcastle, north of Sydney, to ruin Japan coach Eddie Jones's return from a four-match ban for abusing match officials.
After their thrilling 33-31 victory over Australia in Sydney last week, where they rallied from behind four times, Ireland tightened up their defence and dominated possession.
But they were still guilty of some silly errors and their set-piece struggled to fire.
Ireland went to the break with a 19-13 lead after a scrappy first half and stayed focused to complete the job with four players – Sean Jansen, Billy Bohan, Sam Illo and Bryn Ward – making their debut.
"The scoreline flattered us, but delighted for the whole group," said Farrell.
"It was far from perfect and there were a few errors out there but we stuck at it and kept squeezing them until the end.
"We didn't convert all our chances but we stayed in the fight and played at the right end of the field when it mattered at the end of the game.
"We'll take that, sometimes that's rugby."
Ireland's winning run will be put to the test next week when they travel to Auckland and an Eden Park cauldron for a blockbuster showdown with New Zealand.
The All Blacks are also two-from-two at the inaugural 12-team tournament, backing up their 34-32 victory over France with a 47-17 romp against Italy.
"We had to fight hard for that one and stick in it," said Ireland captain Tadhg Beirne.
"Our set piece didn't function as well as we would like tonight. That happens in games, but we'll look at that for sure, and we'll be good to go next week."
'EXECUTED WELL'
Japan host Six Nations champions France next, with Les Blues on a high after crushing Australia 42-26 in Brisbane with a rampant second-half display.
"We came out with a game plan and I think we executed it pretty well in the first half," said Japan captain Warner Dearns.
"I think in that second half, we got a bit stuck in how we controlled the game and let Ireland play the game that they wanted to play."
Farrell made nine changes to his starting side, with an eye on the All Blacks clash.
Japan, who were brimming with confidence after beating Italy at home a week ago, made just one change with Taira Main replacing Kippei Ishida on the left wing.
Main was in the thick of the action after three minutes when Ireland's Ronan Kelleher put too much on a lineout throw and he gleefully collected to dash 60 metres to the line.
Ireland quickly hit back when Ulster flanker Nick Timoney dived under the posts.
A soft penalty allowed Matsunaga to restore Japan's lead on 17 minutes in front of 11 021 fans at McDonald Jones Stadium, a host venue for the 2027 World Cup.
Ireland settled and began patiently building phases with the pressure rewarded when prop Tom O'Toole crashed for a 12-10 lead.
Matsunaga slotted another penalty to edge in front but Ireland kept their composure.
A maul worked efficiently to allow Craig Casey to fire the ball out the back to Robbie Henshaw who burrowed over for a 19-13 lead.
The second period started well for Ireland when No 8 Jansen barged over after a lineout.
Japan came storming back with a converted try for replacement hooker Hayate Era to close the gap to six points with 22 minutes left.
Harry Byrne nailed a crucial penalty 10 minutes from time and a converted try by Tom Stewart at the death sealed the deal.