Devin Toner has admitted he must ‘front up’ against Romania to win back his starting place in head coach Joe Schmidt’s first-choice World Cup line-up.
The Leinster lock was an integral part of Ireland's back-to-back 6 Nations triumphs, but was dropped by Schmidt for the start of the World Cup.
Toner admitted he must raise the stakes after a poor showing in Ireland's final warm-up match, a 21-13 defeat to England at Twickenham on September 5.
Ulster powerhouse Iain Henderson slotted in to fine effect in the 50-7 opening Pool D win over Canada in Cardiff, leaving Toner playing catch-up.
"It's a huge opportunity for me personally and hopefully I can take it," said Toner, ahead of Ireland's clash with Romania at Wembley on Sunday.
"It's absolutely massive.
"I was obviously disappointed not to be involved last week but it just reinforces the fact that everyone has to perform in every game and you take every game in isolation.
"One hundred per cent Iain's performance last week increases the pressure.
"You can see the competition for places now, there's real quality throughout.
"And it just reinforces the strength in depth. Hendy's playing brilliantly well so I've really got to front up this week."
The fast-improving Henderson has been backed to become an Ireland mainstay for years to come, and punched holes with ball in hand against Canada.
Toner is a 6ft 11in lock who stands aloft as the tournament's tallest player and will lead Ireland's line-out in forming a new lock partnership with Donnacha Ryan at Wembley.
It would have been easy for Toner to claim he missed out on Canada selection purely on rotation - instead the straight-talking second row held up his hands on his below-par showing against England.
"Any time you get a bit of disappointment, you look back at past games and see what you need to improve," said Toner, feeling the heat from Henderson.
"I have a pretty good idea how that I haven't been getting on the ball a lot in the last couple of games, and mainly a couple of my defensive stats weren't great.
"So I think they were the two main reasons.
"You do look back at what you need to improve and obviously Hendy is a fantastic ball carrier.
"If I can emulate him it will be good, but I don't know.
"Defensively it's just about getting the reps and getting off the line, actually making the tackles.
"I think you saw in that England game that I slipped off Joe Marler when he went through, so it's just about getting the bite in the shoulder and getting your feet underneath you.
"I have an idea of what I need to improve on and Joe just reinforced it, but it is good to know where you need to work on."
Ireland defence coach Les Kiss admitted Toner needs to raise his level now in order to contest selection for the pivotal pool battles against Italy and France.
"I wouldn't say he has to counter what Hendy did, but from his own perspective he was disappointed with his performance against England," said Kiss.
