Gray scored in the comfortable rout.
“It was nice to get 60 minutes in the tank and get on the scoresheet," said Gray.
“That was our first game on the proper pitch and it was good to get the cobwebs out of a system.
“We go off to Austria next week for two games so I think we should keep up the hard work, get more results.
“It is important to top up our fitness but the results are important.
“We have Manchester United at the start of the season, we have started how we mean to go on."