The goalkeeper produced four game-changing saves to inspire the Saddlers to a 2-1 victory over Pep Clotet’s side on Saturday.
Roberts made spectacular stops to twice deny James Henry as well as Wes Thomas and Jon Obika.
But the 23-year-old said his performance wouldn’t have been possible without the support he receives in training from coach Neil Cutler and fellow glovesman Mark Gillespie.
“On a personal note, I was delighted with my performance but that is what I am in the team to do,” the Willenhall-born shot-stopper said.
“I train day in, day out with Neil Cutler and Mark (Gillespie) and we work on similar scenarios so when we are called upon we are ready.
“In football you often don’t have a lot of time to think. So if you work on different scenarios on the pitch it becomes second nature and you will keep doing the right things.
“It’s like a striker, they practice finishing in training so when they get the ball on the pitch they know what to. Goalkeepers can do the same.
“There are still games when you are off form and there are games when you are on it.
“But there are also times when you just think ‘this is my game’ and thankfully Oxford was one of them.”
Roberts was snapped up by Walsall’s academy back in 2012 and has been the club’s No.3 over the past couple of seasons.
But he was promoted to No.2 at the start of the 2017/18 campaign and admits he is proud of the way he has now forced his way into the team.
“I do feel different now,” he added. “I’ve come in this season as a No.2 having previously been a nNo.3. I went on loan to Chester last season and played games.
“Coming in as a No.2, my challenge is to become a No.1 and play more games and be comfortable in games.
“The way I have burst through is something I am proud of. I have been here now for many years. But to come through the way I have this year is a personal highlight.”