Flanker Peter O'Mahony has warned his fellow Ireland players that their world number one status has put a big target on their backs at the Rugby World Cup.

Andy Farrell's men have topped the global rankings for more than a year following last summer's historic series success in New Zealand.

Ireland begin the World Cup on Saturday afternoon against underdogs Romania seeking to stretch their national-record winning run to 14 matches.

The Six Nations Grand Slam champions defeated Italy, England and Samoa in their warm-up matches but, as head coach Farrell experimented with his squad, did not fully convince.

O'Mahony, who will line up at openside flanker in Bordeaux, feels Ireland can benefit from the trio of disjointed displays as they bid to prolong their impressive run of results.

"We've missed a few beats certainly over the last few weeks but I think a lot of it has been good for us," he said.

"Not that we needed a reality check but it's just been a reminder, which is great before a World Cup, that teams are going to be at their very, very best.

"And particularly now that we are world number one we've a big target on our back. There's no point in putting it otherwise.

"Every team you play is going to be at their very best to try and knock you over and I think it was a good reminder for us over the last few weeks of the different types of games and the way to approach them."

Munster back-rower O'Mahony is at his third World Cup following quarter-final exits to Argentina in 2015 and New Zealand in 2019.

Ireland were also world number one ahead of going to Japan under Joe Schmidt four years ago but had held the position for only a matter of weeks.

"It's the biggest stage of all for us that we can get to, I'd argue with most people over that," said O'Mahony.

"It's where you want to be, it's the cycle of every international team who's trying to play in the World Cup or who wants to be in the World Cup.

"Four years we've been planning this, the management team.

"We've been very vocal about how we've designed the last couple of years based on getting to this point using all those experiences that we've gone through over the last couple, three years, to best effect here and how we can use them in our performances over the next few weeks.

"It doesn't get any bigger than this stage."

READ MORE: Kolisi going into RWC opener against Scotland with playoff mindset

Follow all the Rugby World Cup fixtures in our live score centre

Selected matches will also be available on SABC Sport.com's live streaming channel

Local Start Time Venue	16 Dec at 01:00 PM
Local Time	16 Dec at 06:00 PM
Toss	Belize won the toss and chose to batting
Country	South Africa
City	Pretoria
Venue	St Albans College Ground
Established	0000
Result	Suriname won by 4 wickets

Finished ICC Mens T20 World Cup Americas Sub Regional Qualifier