Tackles and mauls were the stress relief for 18-year-old Williams, one of three members of the Wales under-20 side who is balancing the World Rugby U20 Championship with their A-level exams.

Williams, a pupil at Cardiff Welsh medium school Ysgol Glantaf, sat chemistry in the morning, was driven hastily across the city of Rosario back to the stadium just in time to help his side defeat the hosts 30-25 in a contest that kicked off at 1pm.

"It was a bonus to have him as an option off the bench, originally we thought he would take the exam in Buenos Aires and would miss the match," head coach Gareth Williams explained.

"We have three players involved with exams, we are balancing it."

The day before the Argentina victory Williams sat a biology exam, while he also took a maths exam along with teammate Aneurin Owen, 18, ahead of Wales' 32-13 defeat to France.

This week Williams, the son of former Wales international Owain Williams will sit further exams in chemistry, maths - with Owen - and biology.

Owen suffered a head injury after colliding with a teammate against Argentina, and while he was not fit enough to play against France, he is fit enough for a maths exam.

Aneurin Owen receiving treatment for a head injury in the match against Argentina. He is expected to be fit for his maths exam this week

Their teammate, Leicester Tigers fly-half Sam Costelow, 18, had to travel even further to do his exams.

Different regulations meant he was forced to travel four hours and almost 200 miles to the capital city of Buenos Aires with a chaperone from the Wales management team in order to sit a geography exam.

Team manager Darren Joy has been responsible for making the arrangements, having contacted each of the respective schools three months ago to begin making plans.

While all the schools were willing to help, Joy endured a lot of red tape obtaining the requisite paperwork to ensure the players did not have to pick between the tournament and their education.

Sam Costelow came off the bench to play against France, having been in Buenos Aires doing geography A levels

"The work the boys have put in is amazing, especially if you add in the fact that for a lot of them, it is their first time being away from home for a prolonged period," head coach Williams added.

"They have needed to keep their focus on two fronts with the rugby and the exams and that has been really impressive from them.

"To be able to set-up the exams over here in Argentina, we give a lot of credit to team manager Darren Joy.

"He has made it as comfortable as possible for the boys to complete their exams and make sure it doesn't impair on their preparation or performance."

Wales conclude their group matches against Fiji in Santa Fe on Wednesday.

For three of the squad, it will be a test they relish.