JAMIE Roberts says that Wales have swotted up and are ready to fire at the World Cup.

The 28-year-old centre has shaken off a rib injury suffered in the August warm-up victory against Ireland in Dublin and will be a key figure for Warren Gatland’s men.

Roberts will play for Harlequins over the road from Twickenham after the tournament but he doesn’t want to be heading for the Stoop too soon.

The two-time Lions star is unlikely to be risked in Wales’ opener against Uruguay has declared himself in prime condition, mentally and physically, for the crunch clashes with England, Fiji and Australia.

“You have to peak as a player every two years, for the World Cup and the Lions because they are the ultimate,” said Roberts, who qualified as a doctor at Cardiff University and who is set to continue his studies at Cambridge.

“2009, 2011, 2013 and this year are the biggest stages you can play on as a player, moments you really want to grasp.

“I am in the right frame of mind and physically I feel really good. We have had a tough 10 weeks to prepare for this and I use the analogy of an exam.

“If you work hard for an exam, you are in a much better place while if you have not done enough, you are bricking it.

“I have done the preparation physically and mentally I am there because everything in my life is taken care of beyond the World Cup. I can completely focus on the rugby.

“I am happy and relaxed; I have done my homework and I am ready to go.

“I feel comfortable having done all the hard work. It was hell at the time but I feel happy going into a World Cup at my peak physically and relaxed mentally.”

The loss of key duo Leigh Halfpenny and Rhys Webb has hit Wales’ chances of making it out of a nightmare group that includes hosts England, Australia and Fiji as well as whipping boys Uruguay but Roberts remains confident.

“We know that if we get it right four times for 80 minutes we will get through to the quarter-finals,” he said.

“The physical stuff is done now and it is about getting minds right, getting the gameplan right, taking confidence into the first game against Uruguay and making sure that mentally every minute counts in the four pool games and all 31 lads are switched on all the time.

“Traditionally both England and Australia make the knock-out stages at the World Cup,” he continued.

“Australia have proved their quality in this year's Rugby Championship. They seem a bit like France, peaking every World Cup.

“They will be a very difficult team to beat, no doubt. Our record against Australia comes up every time we play them, how in the last 10 minutes we always get pipped by a few points but we are hoping for a different result at Twickenham.

“England are the same with World Cups, always seeming to pick up their performance. The momentum they will gain from a home tournament is pretty significant.”