The Irish head into Saturday's Guinness Series opener against South Africa at Aviva Stadium without their two injured Lions captains Brian O'Driscoll and Paul O'Connell.
Seasoned campaigners Stephen Ferris, Rob Kearney, Rory Best and Sean O'Brien have also been lost to the treatment room.
Robbed of six key personnel, Ireland face seemingly insurmountable odds tomorrow even if a run of three wins in four Test against the Springboks is encouraging.
But rather than wilting before the challenge awaiting at Lansdowne Road, Sexton has demanded his team-mates begin the process of transforming themselves into household names
"We have to believe that we're good enough," said the Leinster fly-half.
"We're obviously missing a lot of very good players throughout the team, but at some stage of their careers those guys that we're missing would have been the new kids on the block.
"It's time now for us to step up and start building the type of reputations those guys have.
"They developed those reputations by producing week-in, week-out for Ireland and hopefully we can start doing that now."
Little has gone Ireland's way as they seek to end a sequence of successive Test defeats dating back to England in the final match of the RBS 6 Nations.
Completing the run was the summer whitewash by New Zealand, who inflicted a humiliating 60-0 rout upon an Irish team that just a week earlier was on the brink of a first victory over the All Blacks.
Beating South Africa would ease the anguish of that result in June and Sexton insists the experience could yet prove useful.
"We took a lot of positives from the first Test and then learnt a lot from the second," he said.
"In that third Test we made three mistakes and were 21-0 down, then we were chasing the game which is very dangerous when you're playing the All Blacks.
"They picked us off and we've learnt from that if we ever go behind again, we'll never chase it that hard.
"If we can be in it with 20 minutes to go, well anything can happen in Test rugby
"We're concentrating on our performance against South Africa and trying to get things right when we have the ball."
The losses in personnel has forced coach Declan Kidney to select a much-changed side.
Leinster's South African-born hooker Richardt Strauss makes his debut - he will line-up opposite cousin Adriaan - while lock Mike McCarthy and flankers Peter O'Mahony and Chris Henry have 13 caps between them.
Simon Zebo starts at full-back in his second Test appearance, while Keith Earls has replaced O'Driscoll.
The changes also extend to the captaincy with Jonathan Sexton losing out to Leinster colleague Jamie Heaslip, who will lead the team for the first time.
"I'd never like to come out publicly and say I'd like to be captain," Sexton said.
"It's more something that gets offered to you if the management believe you're the right man.
"I spoke to Declan briefly about it last week. For him to come and talk to me about it was an honour.
"I can imagine how Jamie is feeling, it will be a very proud moment for him. He deserves it, he's an outstanding professional.
"Maybe one day.....I've a lot to learn as a leader. Maybe it was the right decision at the time.
"I think Paul O'Connell would have been captain if he was fit. It's a pity he's not playing."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.