Fiji could pose Ireland more problems than South Africa in Dublin on Saturday, Rob Kearney has warned.
Ireland thumped a sorry South Africa 38-3 in a record win over the Springboks at the Aviva Stadium last weekend.
Fiji lost out 19-10 to Italy in Rome on Saturday, but British and Irish Lion Kearney believes the Pacific Islanders could prove a tougher challenge than the below-par South Africans.
Flankers Jordi Murphy and Sean Reidy have joined Ireland's squad, to offset Tommy O'Donnell's shoulder issue and Dan Leavy's hamstring complaint.
Asked if the Fiji fixture could prove tougher than the South Africa encounter, Kearney replied: "Potentially, Fiji rested a few guys at the weekend, so they're eyeing it up in some shape or form.
"We know the threats they have and some of their guys are playing as good as they have over the last few years.
"They're definitely a team on the up and improving a huge amount.
"Individually we know they're very good, but collectively they're improving.
"They look like much more of a well-coached side. It's definitely going to be a big challenge."
The Irish Rugby Football Union (IRFU) has confirmed Saturday's Fiji clash as a 51,000 sell-out, and Leinster star Kearney expects Fiji's flair-filled operators to light up the Aviva Stadium.
Inventive talents like Racing 92's ball-playing lock Leone Nakarawa will pose fresh challenges for Joe Schmidt's men, with 31-year-old Kearney admitting the hosts are wary of the attacking firepower on show this weekend.
"We watched a bit of it this morning, they were pretty good," said full-back Kearney of Italy's 19-10 win over Fiji.
"They've got some world-class individuals who we know about through the Top14 and the Guinness as well.
"They pose a massive threat individually, the key for us is to make sure our systems are in place really well and we don't knock off to give them those individual opportunities.
"The same way South Africa at the weekend have so many talented guys, but if we can work together and make sure there's no chinks in our defensive line then it's tough for them to showcase their talents."
Kearney won his first cap since the Six Nations in Saturday's potent win over the Springboks, having shaken off a host of injury issues in the last couple of years.
Boss Schmidt had paid tribute to Kearney's Test longevity last week, and now the full-back has admitted he has one eye on reaching World Cup 2019.
"I've learnt a lot over the years that you can't look too far ahead; you can pick up injuries any time that can dictate your immediate future," said Kearney.
"But I'm massively hungry to play in this team and my ambitions are firmly on going to the next World Cup.
"It was great to be back out there (against South Africa), obviously I've missed a lot of rugby over the last few months so it's nice to have those minutes under my belt and get the win too."