Conor Murray admits Ireland's impressive record-breaking winning run will not count for much once they begin their Rugby World Cup campaign.

But Murray, who is preparing for his fourth World Cup, admits the tournament is a "different animal".

"It (form) going into a World Cup doesn't count for much," he said.

Murray is one of three scrum-halves in the Ireland squad alongside Jamison Gibson-Park and Craig Casey.

And he added: "You have to bring your best rugby when you get to the tournament, when the competition kicks off for real.

"But we know how good the team can be. We also know how hard we have to work to get to that level and be there every week.

"The summer series was good and people got hit outs and we feel match fit now, but it's a different animal by the time the World Cup comes around.

"We know where we can go as a group, the confidence is really high."

'Ireland know what's coming from South Africa'

Ireland have warmed up for the World Cup with wins over Italy, England and Samoa, the latter of which featured a man-of-the-match performance from Munster scrum-half Murray.

The Irish face Romania, Tonga, South Africa and Scotland in Pool B in France, with the Springboks having offered a emphatic reminder of their credentials by beating New Zealand 35-7 at Twickenham in their last warm-up game.

Ireland take on South Africa in their third pool game and Murray, who worked with Boks head coach Jacques Nienaber and his assistant Felix Jones at Munster, says he knows what to expect from the world's second-ranked team.

"We know what they're like," said Murray, who has 107 caps for Ireland.

"You could say New Zealand were poor, but I thought South Africa put them under so much pressure it made them make mistakes.

"A lot of us have been coached by Jacques and Felix and we know what's coming. Well, we think we know what's coming. Jacques is always going to pull something out of nothing and something you didn't expect.

"We've been watching South Africa and everyone else for a long time. I'm sure they will feel really good about where they're at because that was a really good New Zealand side and they made them look not so good."

Ireland saw off Samoa in unconvincing fashion on Saturday with Murray scoring a crucial try in a 17-13 win in Bayonne.

While not at their best, Murray feels delivering a result on an off-night will stand Andy Farrell's side in good stead for the World Cup.

"Along that road we're going to have games when things don't go perfectly and we have to find a way," said the 34-year-old.

"The World Cup could be like that and probably will be like that, it won't go perfectly.

"There's going to be nights like this (Samoa). The atmosphere was really hostile, in a good way, but we're going to have to deal with that kind of thing as well.

"We know how much pressure there's going to be, how the atmospheres are going to be."