The 15-year-old, who captained the Young Lions on his international debut against Wales in The Victory Shield last October, beat the Ashton-on-Mersey school record set by Campbell in 1989 – recording a time of 10.99 seconds.
Football fans need not worry, however, as despite his astonishing achievement on the track in his very first competitive race, his eyes remain fixed on achieving his goal of making it pro' at United.
“He was always kicking a ball round the house so I said take him to a football club before I’ve got no furniture left”
Mum, Nylva, on football-mad son RoShaun
The youngster, who signed for United aged nine having played football since the age of three, stays in Sale five days a week so he can fit in training at the club’s Carrington training ground along with his school work at Ashton-on-Mersey.
And it is playing professional football for United and England once he finishes school next summer that he dreams of.
Speaking to the Manchester Evening News, he said: “Ryan Giggs is my hero I suppose because he has stayed with the club, and when he was acting manager he gave young players a chance.”
And on his impressive time, Williams said: “I didn’t know I had beaten the record until the next day at school when my teacher told me. It was just a school sports day so we all had to run.”
Williams’ mum, Nylva Green, added: “I already called him my little Usain anyway, but he doesn’t like it. We’re so proud it really is an amazing achievement.”
She added: “He was always kicking a ball round the house so I said take him to a football club before I’ve got no furniture left.”
And it is not just Williams’ family who have been impressed by RoShaun’s quick feet – the man whose record he broke has also wished him well.
Olympian and Manchester-born Campbell, who won gold for Great Britain in the 4x100m relay at the 2004 Athens Olympics, was quick to offer his congratulations to the new record holder via a video message.
Campbell, aged 40 and who held the previous record of 11.13 seconds, said: “I’ve always said anyone who can run under eleven seconds has got a lot of natural speed, it shows that he’s got massive ability. I wish him all the best.”