Wales player Sam Warburton during training© Stu Forster/Getty Images

Wales' World Cup captain Sam Warburton has revealed he "thought the worst" after suffering a shoulder injury during training earlier this month.

Warburton missed Saturday's impressive tournament warm-up win against Six Nations champions Ireland in Dublin, resting his shoulder instead, although he looks set to be involved when Italy visit the Millennium Stadium at the weekend.

Cardiff Blues flanker Warburton will embark on his second World Cup campaign as skipper, but he admitted that the north-Wales training camp mishap worried him.

"We did a 15-on-15 session and I got a turnover under the posts, and of all people Jake Ball, who is 126-127kg, came flying into my shoulder," Warburton said.

"It was perfectly legal, but it caught me right on the button where I have suffered before with nerve damage.

"Initially, I was a little bit worried because when I had it first time it was a three-month job, and on the second it was two months. When I took my T-shirt off in the hotel, I could not lift my arm up and I thought the worst, as you do.

"Luckily, within two or three days it recovered - 100 percent quicker than it had in the past.

"It was a minor scare, so with the Ireland game we thought for the sake of three or four days' extra rest it was not worth risking re-injuring it and missing a month or five or six weeks. It was better safe than sorry.

"I was panicking for a good couple of days. With nerves, you do not know how they are going to recover. When it was three months, they did not diagnose that from day one -- you had to take it each day at a time.

"When you do a ligament, you can have an MRI scan and they tell you grade two, three to five weeks and you know what you are doing. With nerves, it is about waiting, and after three days the improvement was massive."

Warburton's last World Cup experience was one of abject misery after being sent off against semifinal opponents France in Auckland for a dangerous tackle on Vincent Clerc.

Wales lost only 9-8 despite being down to 14 men for more than hour, and now, four years on, they find themselves in the same pool as England and Australia, with only two quarter-final places available.

"Get out of the group stage and into the quarters, and I back Wales to beat anyone on our day," he added.

"Getting out of the group is going to be incredibly tough and will probably take as much effort as it did to make the semifinals four years ago. That's how much tougher our group is."

Warburton, meanwhile, has lavished praise on his fellow World Cup squad openside Justin Tipuric, who was man-of-the-match in both warm-up games against Ireland this month and has arguably never played better.

"I could have picked him for man-of-the-match after 30 minutes [in Dublin], Warburton said.

"I have always said that when people ask me about openside flankers in world rugby, I will always pick him [Tipuric] as one of the best. I have played against quite a lot of opensides now, and he is one of the most influential and best in world rugby."