Irish backrow forward Caelan Doris says he is confident Ireland's attack can inflict serious damage on defending champions South Africa if they match them for physicality in their Rugby World Cup Pool B match on Saturday.

The 25-year-old said he and his teammates were prepared for the cauldron of the Stade de France and the 80 000 spectators, their confidence bolstered by having beaten the Springboks last November in Dublin.

Doris concedes their opponents have "evolved quite a bit" since then but so too, he added, have the Irish: ranked No 1 in the world they secured the Six Nations Grand Slam in March and are now on a 15-match unbeaten run.

The run includes a 19-16 win over the Springboks in Dublin last November which Doris says has "definitely" given them confidence.

"I think looking back to the game (against the Springboks) we knew we had to be on it in terms of our defence, in terms of our physicality.

"That week in Dublin, we took a step up and we know we require the same this week.

"I think if we match them there we've a lot of belief in what we can do in terms of our attack.

"We've shown some of that over the last couple of weeks but it's definitely a test."

Ireland's attack has certainly torn both Romania and Tonga to shreds, running in 20 tries with Doris creating one and scoring one in their 59-16 win over the Tongans last Saturday.

However, he is under no illusions the South Africans, also with two wins under their belts, will be nowhere near as generous as their previous opponents.

Doris was especially impressed by how they performed, both in offence and defence, when they inflicted a record 35-7 defeat on fellow three-time world champions New Zealand in a warm-up match last month.

He puts that performance largely down to one thing.

"Physicality is the word which springs to mind," he said.

"I remember being shocked at just the sheer size of them, playing them in November.

"The fact they kind of do a 6-2 (six forwards, two backs) or even 7-1 sometimes off the bench and have massive reinforcements as well...

"Obviously the physicality is tied into their set-piece. They've got a great maul, a very strong lineout and scrum as well."

'PALPABLE INTENSITY'

Doris, who managed to complete a psychology degree despite his rugby commitments, said Ireland are not lacking in intimidation either.

"We have good ball-playing forwards," he said.

"We have multiple threats in that we have good carriers but we also have people who are capable of tipping the ball on, giving passes, giving wider passes, so it is not just tuck and carry.

"There is footwork, passes and the carry threat. Hopefully defences find that a little bit intimidating."

As for intimidating atmospheres, Doris says previous experience of playing at the Stade de France – when France beat them in their Six Nations match last year – will help.

They will also be aided by not having to face the hosts. Thousands of Irish fans, many more than usually follow them abroad, will be in the stadium to support them.

"I remember being quite taken aback by it going into the game," said Doris.

"From the warm-up there was a palpable intensity in the atmosphere.

"Having experienced it once, it is an easier thing to visualise and be aware of.

"Hopefully there will be a good few more green shirts there as well."

Doris says older heads in the squad like captain Johnny Sexton and scrumhalf Conor Murray have been helping them prepare mentally for the blockbuster match.

Another wise head, forwards coach Paul O'Connell, has been drawing on his experience having captained the Irish at the 2015 World Cup.

“There is a special feeling to the week," said Doris.

"We know we need to deliver our best and what comes with that is maybe little extra conversations or an extra walk-through in the evening.

"Paulie's point was: 'Enjoy the week and when you're off, you're off. Don't get over-stressed about thinking you have to do way too much this week. A lot of the work is done.'"