Rome - Ireland skipper Peter O'Mahony conceded there was "plenty of work" to do if the Grand Slam winners want to retain their Six Nations title after labouring past Italy.

Ireland had to fight back from being behind at half-time to win 26-16 but still managed to score four tries to leave Rome on Sunday with the precious bonus point they had targeted.

"I'm not going to sit here and say we're delighted with the result," said O'Mahony, whose side had trailed 16-12 at the break.

"I was proud of the way the lads handled the second half because, you know, we were under the pump, we were under pressure coming in at half-time."

Wales beating England 21-13 on Saturday means Joe Schmidt's side have a chance of retaining their Six Nations crown.

Their final two games are against France in Dublin on March 10 followed by a finale against Wales in Cardiff the following week.

Unbeaten Wales are the only team who can complete a Grand Slam. They top the table with 12 points, England are second on 10 with Ireland on nine.

"England not winning opens the door for us," said Ireland coach Schmidt.

"Wales are in the strongest position now they've won three out of three, it's going to be a huge match in Cardiff for us."

France lost their opening two matches but were much improved in beating Scotland 27-10 on Saturday.

"France looked like they'd built a bit," Schmidt added.

Ireland's performance was far from fluid in windy conditions in Rome, despite two tries in the first half from Quinn Roux and Jacob Stockdale, and a further two after the interval from Keith Earls and Conor Murray.

Edoardo Padovani and Luca Morisi touched down to give Italy a four-point lead at half-time as the Azzurri eyed a first Six Nations win at the Stadio Olimpico since they beat Ireland in March 2013.

But in the end the Irish condemned them to a 20th consecutive defeat in the tournament.

"I challenged the team at half-time," said Schmidt.

"I said, 'this is perfect. Now we can find out can we work our way back into the game? Can we get back in control and can we make sure that we can get the full account from this game?'

"I'm proud of the way the players managed to stay calm enough and deliver what we needed.

"We'll go home happy with the points but certainly not the performance," he added.

Ireland's simmering frustrations boiled to the surface when star flyhalf Johnny Sexton kicked a towel in anger after he was replaced late in the match by Test debutant Jack Carty.

"We struggled at times to be cohesive," said O'Mahony, who took the captain's armband for the seventh time with regular skipper Rory Best rested.

"We know what's there, we know we're not far off, but we've just got to figure out what we need to do to unlock it a little bit."

For Italy it was their third defeat after Scotland beat them 33-20 in Edinburgh and Wales won 26-15 in Rome.

They are bottom of the Six Nations table and next play England in Twickenham on March 9 and finish their campaign against France in Rome.

"We've a mountain to climb," said Italy coach Conor O'Shea.

"Stockdale's first try, you don't give that away at an international level. There's a lot of tough days and climbing ahead, but we're climbing.

"We'll dust down and get ready for Twickers."