There are fewer crueller things in sport than missing a World Cup through injury.

Especially when you are in the prime of your career. That is what Wales fly-half Gareth Anscombe is coming to terms with as Wales fly out to Japan this week.

Anscombe suffered a serious knee injury against England in the opening warm-up match last month, which he confirmed should rule him out for up to nine months.

"I guess when Japan comes around that will be the hardest time to deal with it," said Anscombe.

"It was tough to take after a thorough eight weeks in a gruelling training camp.

"The most frustrating thing was that I had such a fitness base and my body was feeling fit and healthy.

"For it to be taken away was a tough pill to swallow and I can't say it has fully hit me yet.

"Those are the things I will miss, even stepping out of the Wales WhatsApp group a couple of weeks ago was tough.

"I had been working towards this tournament for a long while and felt I could have played a key role in helping the team achieve something pretty special.

"So I suppose the hardest time for me will be waking up and watching the boys play in Japan."

His World Cup dream ended with what appeared an innocuous incident as he sidestepped England full-back Elliot Daly. Anscombe continued afterwards and even kicked a conversion before being forced off.

"It was a funny 20 minutes," said Anscombe.

"I was feeling good and it was all done on the run down the sidelines and stepping Daly.

"I went to step him running full speed, a motion I have done countless times before.

"I just felt a pop and remember hitting the deck and did not feel right. We checked the knee and structurally it was positive so we did our best to carry on.

"I was then kicking the ball out of hand and it felt looser not stable. I did a chip kick at the end, a shot to nothing, and I knew I was coming off."

Anscombe left Twickenham on crutches that night, but initially did not fear the worst.

"I was still optimistic, because I was able to play on, that there was a chance it could be a grade one strain with four or five weeks out," he added.

"That would have still given me the chance to be alright. The fact it was an ACL tear with a seven to nine month rehab was something we did not predict."

Anscombe had established himself as Wales' first choice fly-half ahead of Dan Biggar and played an integral part in the Grand Slam success and record 14-match unbeaten run.

"I have been fairly happy with the last 18 months," said Anscombe.

"It has been great to be a part of the Wales environment and going on the winning run and achieving something special.

"The fact the team got to number one in the world briefly should be respected and recognised because it had never happened before.

"Although it counts for nothing it is nice to achieve that and we have gone a long way to establishing ourselves as contenders in world rugby."

So how does Anscombe feel Wales will fare at the World Cup?

"I am optimistic and it is why it is going to be so hard to watch because if they can go and achieve what I think they can, it is tough to sit on the couch as a spectator," he said

"If they can get to the semi-finals anything can happen. When it gets to the tight games we have shown we are good in those situations."

After joining Ospreys from Cardiff Blues, Anscombe will miss most of the season at the new region and hopes to keep himself busy.

Anscombe has set up a company which he describes as a search-engine comparison site for fitness, sports and wellbeing, which will be launched alongside former Wales team-mate Alex Cuthbert among others. The app is expected to be launched in October.

The 28-year-old has been pictured doing his shopping on a mobility scooter as he faces a battle to return to full fitness.

Anscombe says he received well wishes from across the rugby world and revealed the most random message was a tweet from former WWE champion John "Bradshaw" Layfield (JBL).

His long-term international targets are getting on Wales' tour to New Zealand in the 2020 summer and the British and Irish Lions trip to South Africa the following year.

"I have not set any goals yet on when I will return, but I would like to play some rugby at the back end of the season," said Anscombe.

"I will need to try and get myself fit for Ospreys and hopefully back playing for Wales.

"Hopefully, I will get on the tour to New Zealand in July, but there is a long way to go and a lot of boxes to be ticked.

"There is the 2021 Lions tour, but there are a lot of good players and a hell of a lot of competition, particularly in my position.

"It would be fantastic to achieve that after watching the effect it had in New Zealand in 2017.

"I would love to do that, but there is a hell of a lot of rugby before that."