Jason Roy is just one shot away from "tearing it up" in Test cricket according to his former county captain Gareth Batty.

Roy is ranked as one of the top 10 one-day batsmen on the planet and played a leading role in England's World Cup triumph earlier this summer, but has endured a difficult start to life in the five-day format.

He averages just 9.5 as an opener in the first three Ashes Tests and has been moved down to number four for this week's crunch clash at Emirates Old Trafford.

England hope he will thrive lower down the order away from the new ball and Batty, who played 19 times for his country as well as captaining Roy at Surrey, is sure big runs are around the corner.

"Anyone who has seen Jason close at hand or played with him knows there's not a question over his ability or his technique," Batty told the PA news agency.

"I still think Jason's selection is absolutely perfect for England, it's the right call. I think he is going to clean up in Test cricket and go on to have a brilliant career.

"You only need to look at someone like David Warner, who people called a white-ball specialist, and I think once he gets going Jason will be tearing it up.

"When he plays the ball just underneath himself, and doesn't have his hands out in front, he has incredible ability to strike the ball.

"Once he gets hot he stays hot for a long period of time. Maybe he just needs one shot, maybe it's a poor delivery that he can get on to or maybe it's a really good one that he just climbs on top of and the floodgates will open. But when he gets going...wow, watch out."

Batty believes Roy could go on to succeed at the top of the order but accepts that with most of his first-class appearances for the Brown Caps coming in the middle order – a result of stiff competition for opening berths at the Oval – shuffling the pack could help him this week.

"Jason batting anywhere in the top doesn't concern me, but I suppose going down the order gives him a fraction more of a chance. Particularly if they go well at the top and make the bowlers come back for their second and third spells," he said.

"In his most recent first-class games he's batted four for us and he'll be more accustomed to the process – sitting in the changing room, waiting to bat – so the selectors have given him more of a chance.

"Because we've seen Jason so dominant in white-ball cricket maybe the anticipation was that he was going to come in and get 100 in 50 balls, but that burden is not fair on him, or anybody. Make no mistake, this Australia attack is full of very, very fine bowlers.

"But when he strips it back, plays up and down the line of the ball, he's as good as anybody. He can take them down."