Ireland head coach Joe Schmidt played down the significance of his side becoming world number one after their 19-10 victory over Wales at the Aviva Stadium.
Tries from Rob Kearney, Tadhg Furlong and James Ryan were enough to ease past Wales for the second time in as many weeks.
But despite their ascent to the summit of the rankings, Schmidt was adamant his side were not favourites going into Japan.
“I didn’t realise we were (number one) until the interview after the game, that’s how far away from our thoughts it was,” he said.
“It’s a label and it’s great to get; it’s the first time we have been in that position.
“We have been lucky enough to tick off a few firsts with this group but it’s not that relevant to anyone.
“We all know who the favourites are in this World Cup and it’s not us.”
It had been a slow start to the game for Ireland, who struggled at the line-out for any real fluency during the opening exchanges.
But that all changed when winger Kearney went over on 22 minutes, before Furlong and Ryan – who was named man of the match on the eve of his maiden World Cup – sealed a convincing win for the hosts.
And in their final dress rehearsal before the real business begins in their opening group game against Scotland in Yokohama, Schmidt heaped praise on his side for an impressive display.
“We got a performance we could be proud of – the first quarter of the game we couldn’t hang onto the ball, but I thought we did a really good job defensively and then we built our way into the game and we dominated the last quarter,” he added.
“It wasn’t necessarily pretty to watch but it was nice to get that result.
“Across the board there was a real work ethic out there today – it wasn’t flash, but it was functional, and sometimes when you’re building towards something you want functional.
“I thought we looked dangerous with the ball, but once we got to squeeze them in the 22, we muscled up really well.
“Obviously Scotland have had a couple of good wins against Georgia and a good win against France.
“The focus of a World Cup is huge, so you immediately start to think in terms of the next game.”