Jack McGrath believes Ireland can turn Italy's confrontational scrummaging against them in Saturday's RBS 6 Nations opener in Rome.

Prop McGrath will go toe-to-toe with Italy's combustible tighthead Martin Castrogiovanni, and admitted Ireland will aim to exploit the Azzurri's sometimes volatile set-piece passion.

Toulon prop Castrogiovanni was fined by European chiefs after a foul-mouthed tirade launched at his former Leicester boss Richard Cockerill in December.

McGrath believes Ireland will meet fire with fire at the coal face at the Stadio Olimpico, backing tighthead Mike Ross to handle the pressure despite recently losing his starting place at Leinster.

"They really want to shove their scrum in your face," said McGrath of Italy's no-nonsense approach.

"Their lineout maul too, that's their bread and butter and where they pride themselves the most.

"If we can meet them in that area and maybe go one better that's what we ideally want to do.

"But it's not just doing it once; it's doing it every time.

"If you give them a sniff there's massive confidence there.

"And especially at home the crowd is just going to get behind them and really rally them up.

"So it's up to us as a pack to really get stuck into them early, and turn it around on them.

"They are unbelievably passionate people so it will be really tough.

"But we'll take them on up front first and foremost.

"If we can take that away from them then we're a step towards winning the game."

Sean O'Brien will make his first Test start since November 2013 as Ireland start the defence of their Six Nations title, the flanker finally over 14 months of shoulder problems.

Ian Keatley and Jordi Murphy will make their Six Nations debuts in Rome, with Jamie Heaslip regaining full fitness on Thursday but not risked.

Ireland boss Joe Schmidt has preferred Munster fly-half Keatley to Leinster's Ian Madigan, with Johnny Sexton completing his 12-week concussion lay-off.

Former Leicester prop Castrogiovanni endured a torrid return to Welford Road in December as Toulon lost out 25-21.

The 33-year-old Italy tighthead stormed into the post-match press conference demanding to set the record straight over his acrimonious Leicester exit in 2013.

Cult figure Castrogiovanni claimed regular rugby not money drove his move to Toulon, but his explicit language landed him a 10,000 Euro fine that he had to donate to charity.

While Ireland respect Italy's fervent approach, McGrath admitted the pack at least in Schmidt's side will aim to use that passion to their own advantage.

McGrath also conceded he must be on the money against 107-cap Castrogiovanni, while tipping Ross to cope despite limited rugby at Leinster in recent weeks.

"Castro's been there and done that, he has every trick in the book," said McGrath.

"But with Rory (Best) beside me and Rossy on the other side I'm confident we can go in and do a job and cause a bit of damage.

"I've been watching Castro for years, he's the guy any young tighthead would look towards.

"He's the type of guy you've got to respect but you've got to go in and make him respect you too I suppose.

"Mike is looking well, he's an experienced guy, he knows his body and he knows he's ready.

"The coaches have trust in him that even though he maybe hasn't played in the last few weeks he's in position to put it in there, and he's well able for it."

Schmidt confirmed vice-captain Heaslip is fit after shoulder trouble and should return for the second-round clash with France.

Schmidt also said Heaslip's absence led to the decision to hand O'Brien a start rather than a seat on the bench.

"Jamie trained fully today, if that had been the case on Tuesday the decision might have been different," he said.

"He's 100 per cent fit now, he will train fully next week and that will allow him to focus on the France game.

"His powers of recuperation are second to none, but we just decided to be conservative with it."