Sam Warburton and Justin Tipuric were the flankers in the 21-16 defeat in Cardiff, with Ross Moriarty outstanding at number eight.
Moriarty was replaced in the second half by fit-again Taulupe Faletau - but ex-flanker Williams said Wales "can't drop" the Gloucester man.
"It's working at the minute," he said.
"You keep the same back row. And you've got Faletau to come off the bench."
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Faletau's second-half appearance was his comeback following a knee injury suffered playing for Bath on 24 December.
Cardiff Blues' Warburton, Tipuric of Ospreys and Gloucester's Moriarty also started in Wales' opening Six Nations game - the 33-7 win in Italy.
Williams, who won 100 caps for Wales between 1996 and 2012, has been impressed with the form of 22-year-old Moriarty for club and country.
"He was simply sensational for the time he was on the park last week," Williams told BBC Wales' Scrum V programme.
"You can't drop someone like Moriarty. Again on Friday night for Gloucester against Saracens he was outstanding. If somebody's in that form just keep them going.
"There's always been a debate come Warburton and Tipuric playing together and it's been so far so good in this tournament."
Williams also believes wing Alex Cuthbert responded in style to criticism of his performance in the defeat by England with a try in the Blues' 57-20 win over Treviso.
Cuthbert missed a tackle on Elliot Daly for England's winning try in the Six Nations match and was released back to his region.
Blues head coach Danny Wilson has urged Welsh fans to back the 26-year-old wing while Williams was impressed with the performance of his former team-mate against Treviso.
"It just shows his mental strength," Williams said. "He could easily have had the week off and go and hide but he wanted to play and it was the old Alex Cuthbert.
"It was good to see him back in form."

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The 15-year-old clocked one minute 50.23 seconds over her two runs, 0.96 seconds ahead of Germany's Hannah Neise.
Pittaway's triumph follows fellow Brit Madi Rowlands, who won gold in the ski halfpipe on Sunday in Lillehammer.
Rowlands, 15, added a bronze in the women's ski slopestyle final on Friday.
"When I first crossed the line I couldn't believe it," said Pittaway.
"I felt like I was standing next to me watching me finish - it was so surreal and just like a movie.
"Hannah [Neise] is one of my best friends and we're really happy to be on the podium together. That's been our dream together for four years."
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The wind farm, run by community company Viking Energy, would be one of the biggest in Scotland.
Sustainable Shetland, a group opposed to the development, launched a judicial review.
The challenge, at the Court of Session in Edinburgh, has been adjourned. It is expected to resume at the end of April.
Energy Minister Fergus Ewing granted consent for the scheme in April.
Protesters claim the development is too big and would blight the landscape.
Supporters argue it would raise money for the islands, create jobs and help meet renewable energy targets.
The 370MW wind farm is aimed at powering more than 175,000 homes despite Shetland having a population of about 22,000.
It is estimated the wind farm could bring about Â£30m annual income for the local community.
Wales should select the same back row that started against England when they travel to Scotland on Saturday, says ex-captain Martyn Williams.
[NEXT_CONCEPT]
Ashleigh Pittaway claimed Great Britain's second gold medal of the Winter Youth Olympics, winning the skeleton bob event in Norway.
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A legal challenge to plans to build a 103-turbine wind farm in the centre of Shetland has been adjourned.