Johnstone kept a clean sheet on his Oldham debut in a 0-0 draw with Burnley last night. The Latics report the loan is only for their final two friendly fixtures to cover an injury crisis but the youngster was delighted to make his bow.
"It was a step up as I was playing with and against men," he told the club's official website. "The management and staff were brilliant.
"They were welcoming and that helped me settle. I thought I settled in nicely and I enjoyed it."