Eoin Reddan must produce a performance worthy of scrum-half rival Conor Murray's expectations against Australia, believes Ireland boss Joe Schmidt.
Head coach Schmidt has asserted 51-cap half-back Reddan's selection ahead of British Lion Murray for the second autumn international is to help "grow the squad".
Schmidt is adamant he is trying to foster squad strength - but did challenge former Wasps 32-year-old Reddan not to let Munster man Murray down.
Schmidt said: "Like Gordon D'Arcy helping Luke Marshall who starts in the centres, Conor has been working away, doing his best to help Eoin prepare the best he can for this match.
"We've tried to have the squad being included. The starting XV have a responsibility therefore, so Eoin knows it as much as anyone: Eoin's representing Conor's hopes in the team.
"When you're trying to grow a squad you can't have guys who are solely individually focused. And I think Conor's brought really good things to training.
"You've just to balance the needs and the opportunities for individuals with the greater good of the squad sometimes. We're happy with Conor, but it's about an opportunity for Eoin."
Wary of Australia's "upward curve" under head coach Ewen McKenzie, Schmidt has warned Ireland to stop the Wallabies at source.
"Anyone would acknowledge they were pretty unlucky against England," he said.
"Some crucial decisions didn't go their way, and if they had the result could have been different. Then they didn't really let Italy into the game a week later.
"To put 50 points on a team is pretty impressive, and it's the same thing they did to Argentina in Argentina.
"They are the first team in a long time to do that to Argentina in their own country. So if you do let them loose they will do some damage.
"We've got to try to limit their opportunity to get ball in unstructured situations with a bit of time and space.
"I could reel off a string of pretty threatening runners that they have, even discarding the backs, with Scott Fardy and Michael Hooper running they are pretty dynamic and problematic as well.
"Then Israel Folau out there, and Adam Ashley-Cooper is world-class, he's a pretty complete player.
"So the back-three are dangerous and through the middle Matt Toomua has certainly opened up a fair few teams.
"Tevita Kuridrani is a tall, athletic man, hard to contain.
"So for us there's a fair few challenges, trying to limit their opportunities, particularly with a distribution base of Will Genia and Quade Cooper, who have great passing games."