Even though Scarlets centre Williams left the Millennium Stadium with his right foot encased in a protective boot, he is optimistic of making a quick recovery from toe ligament trouble.
And that will be music to Wales coach Warren Gatland's ears after he saw Test debutant Cory Allen suffer a suspected dislocated shoulder to join British and Irish Lions Test stars Jonathan Davies (ruptured pectoral muscle) and Jamie Roberts (ankle) on the sidelines.
With Allen's Blues midfield colleague Owen Williams not due back in training until this week, Ashley Beck is effectively Wales' only fully fit centre, although the versatile James Hook could be an option.
And the reigning RBS 6 Nations champions have little time to regroup, with their next autumn fixture against Tonga just five days away.
"Someone landed on the back of my leg and it twisted, and my big toe just stretched. But it was nothing to come off for," said Williams, who along with number eight Toby Faletau was Wales' outstanding player.
"It (protective boot) is precautionary more than anything, and it is just to stop my big toe bending over in the next couple of days.
"I will be strapped to the ice machine over the next 24 hours and see how it is. Hopefully, I will be back in training on Monday or Tuesday."
Allen became the fourth back among Wales' original 35-man autumn squad after Davies, Eli Walker and Rhys Patchell to suffer a series-ending injury, with Roberts and his fellow Lion Alex Cuthbert sidelined since last month, while training group addition Tom Prydie (hamstring) is another casualty.
Gatland is due to announce his team for the Tonga Test on Tuesday, with a number of changes likely to include an international debut for 19-year-old Newport Gwent Dragons back Hallam Amos.
Stockport-born Amos moved to Wales at the age of four, making a Dragons debut in an LV= Cup game against Wasps just 28 days after his 17th birthday.
Reflecting on the injuries, Gatland said: "We are a bit short at the moment, although we are lucky we have got Owen Williams coming back to full training, and we will see what the prognosis is with Scott.
"We might be all right with Owen and Ashley, and if Scott's all right. We are a bit short of wingers as well because we did speak about George North playing potentially in the centre."
Wales bounced back from their 24-15 defeat against South Africa to pummel the Pumas through tries from North, Faletau, Mike Phillips and Ken Owens, while full-back Leigh Halfpenny kicked 20 points.
It was Wales' biggest home victory since they beat Italy 47-8 during the 2008 Six Nations, and their most emphatic winning margin for 26 Tests following a 66-0 demolition of 2011 World Cup opponents Fiji.
"It was a good win," scrum-half Phillips said. "We got some young blood in the team, and I thought they fronted-up well.
"If I was going to be really critical, then we missed a few chances and we should have held on to the ball a bit more in the second-half. And we should have really upped the tempo towards the next level, but overall we are pretty pleased."
Phillips' 70-metre breakaway try ensured that Wales made a flying start, from which they never looked back, and he added: "It was important that we got a good start. It was what was needed.
"I thought we started off-loading and were a bit sloppy in the second-half. If we are going to kick on to be one of the best teams in the world then you have to nail those moments and be disciplined.
"You have to be critical because otherwise you are not going to improve."
Gatland said: "We went in with the ambition of not conceding any tries, and we achieved that goal.
"We give the players a framework to work in, but that doesn't mean we want them stifled in any way to play rugby and not to play what is in front of them. If they see opportunities to move the ball, we want to encourage them do that.
"I thought we went out there with the ambition and intensity to put a good Championship team away."
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