The Welsh youngsters can no longer reach the semi-finals of the tournament in Tbilisi, Georgia after opening losses to Australia and England.
On both occasions Jason Strange’s side had opportunities to prevail and Rosser knows small margins have been the difference.
But with small tweaks and improvements, he remains confident that Wales can triumph over Samoa in their final pool game at the Avchala Stadium tomorrow (10am BST) and from there the aim is to finish as high as possible in the world rankings.
He said: “I missed the first game through injury but watching it, it was pleasing to see the boys hit the ground running straight away. Obviously we didn’t come away with the win but we definitely took a lot of positives out of it and showed some areas of our game are particularly strong.
“We took those into the second game and some of the things that didn’t go so well we corrected in a short space of time. That has put a bit of confidence in the boys that we can take things forward.
“In both games it hasn’t been a case of them scoring their points through us not being able to deal with the pressure or their ability. They have got their foothold in games through our mistakes, which we can put right quickly, we know once it clicks we’ll be good.
“It’s disappointing when you look at the England game and see we gave them a lot of tries early on, you can’t help but think what could have been if we played like we did at the end the whole way through.
“It adds to the frustration but we know we have the ability to correct those things – our mistakes gave them those 21-points.
“Now all the focus is on Samoa. We know we have a couple of work ons going into that game, we know they are going to be big and physical so we will make little tweaks here and there but we’re looking forward to it.
“Realistically we just want as high a finish now so that means wins from the next three games.
“We’re taking it each game as it comes and we know Samoa will not be an easy challenge by any means but we certainly want to finish the campaign on a high.”
Samoa also lost to England and Australia, picking up a losing bonus-point against the latter on Wednesday.
Like against any Samoan team, Rosser expects a physical confrontation against the South Sea Islanders but it is a challenge he is relishing.
He continued: “They will be a typical Samoan team. We’re expecting a big, powerful team with strong runners, who like to put a hit on you but we’re looking forward to it.”
Rosser is also enjoying the experience of life off the pitch in Tbilisi, Georgia. The way of life in the Caucacus country are certainly a far cry from that in Rosser’s home village of Abersychan near Pontypool.
But he is enjoying the experience of his first World Rugby U20s Championship on foreign soil, in particular the activities and trips the squad make outside of training.
In the past two weeks Wales U20s have visited Mtskheta, the former capital of Georgia and it’s Svetitskhoveli Cathedral, plus the fourth century Narikala Fortress and the Mother of Georgia statue above old Tbilisi.
He continued: “Tbilisi’s been good. The weather has been cracking so far so the boys are enjoying that and we seem to be in a nice little area where everything we need is on our doorstep.
“It was definitely a different experience at first because Georgia isn’t really a place people think of visiting.
“Obviously our priority is the rugby but to be successful on the pitch you also need a balance between rugby and the nice breaks away and seeing a bit of the local area. The boys know when they are going out they have deserved it because of the work they have put in on the rugby side.
“They’ve been cultural places, with some nice music and sights, which the boys enjoyed. It’s always nice to get out of the hotel and training environment just for a change in scenery and to see what Georgia has to offer.”
Rosser, who is sharing with fellow Dragon Connor Edwards, is well accustomed to life on the road and sharing hotel rooms following a season on the sevens circuit.
He featured in tournaments in the HSBC World Series but looking ahead he is hoping to further push his case for game-time with Newport Gwent Dragons.
He added: “I’m with Connor Edwards, he does snore but otherwise he’s pretty good. I’ve just got used to it now and learned the key is getting to bed before him. I’m probably the messy one but I do know where everything is.
“I thoroughly enjoyed my time with the Sevens. Just taking the short turnaround in games here, I am used to that with the different tournaments.
“With the Dragons I didn’t get a chance to play in the Anglo-Welsh Cup or anything this year because I was in the sevens so it would be good to start with that next season and to try to put my foot in the door.
“There’s a lot of good players in the back-three and a lot of competition but hopefully I can put my hand up for some game time.”
Rosser targets unbeaten streak
Jared Rosser has called on Wales to finish the World Rugby U20 Championship on a high by winning their three remaining games.