Kobe - Ireland wing Jacob Stockdale insisted Japan haven't set the template for beating the Six Nations side after their shock victory at the Rugby World Cup.

Japan beat Ireland 19-12 in the biggest upset of the tournament so far, which emulated their remarkable 34-32 victory over South Africa at the 2015 World Cup in England.

Afterwards, Japan coach Jamie Joseph said his squad had been preparing to face Ireland for three years.

But given Japan fell 12-3 behind early in the match, Ireland wing Stockdale reckoned there was more to their eventual success than careful planning alone.

"I don't know if it's as easy as that; there's a lot more factors there, like a home World Cup and a really passionate crowd," he said.

"I thought the support in the game (generally) was class but there it really was incredible, just so passionate," the Ulster flyer added.

"There's a lot more than just doing analysis to beat a team. I thought they played well and we didn't match it.

"That's the nature of rugby - it's not just that if you do your analysis you'll beat somebody."

Despite the loss to Japan, Ireland remain on course for the quarter-finals heading into their final Pool A match against Samoa.

But after bouncing back from the Japan defeat with a 35-0 win over Russia in Kobe on Thursday, the Irish now have a lengthy break until they face the Pacific islanders on October 12.

Stockdale said that for all Ireland coach Joe Schmidt was presenting a relaxed face in public, the 54-year-old New Zealander was still coming down hard on his players.

"Whenever we're training Joe likes to push the intensity and really build it which is obviously class for us as players, you get that intensity that's almost like a match," he explained.

"It's amazing how much pressure one man can put on an entire team but it's brilliant he does.

"Whenever you're off he's a bit more relaxed and you're able to chill out a bit more, I think he gets a really good balance in his coaching style."