Grant McCann says his Doncaster Rovers side remain a work in progress following their friendly defeat at Grimsby Town.
Rovers suffered a 1-0 defeat at Blundell Park on Tuesday night as they were punished for a disappointing first half performance.
They improved significantly in the second half and were somewhat unfortunate to not at least equalise.
And McCann has encouraged his players to show their ruthless edge.
"It's going to take time," McCann said.
"I've only been in the building a short time, almost four weeks.
"But you see the boys are getting the formation, they're enjoying it and the freedom in the play."
"We're a work in progress, we're getting there," he added.
"The movement, the rotation, some of our general play was very good.
"It's just about finding that ruthless edge that is in the group.
"We're not worried because it is there.
"We had numerous chances to capitalise, definitely in the first half and some excellent play in the second half with some chances.
"It just wasn't to be
"It's pre-season. It was pleasing to get 90 minutes into some of the players again. I thought we came strong as the game wore on and the fitness levels showed definitely in the game that the boys were still going and working hard.
"It's a disappointing result, no one likes losing, but it's pre-season.
McCann was pleased with the performance of trialist Romario Vieira, the former Leeds United midfielder.
Vieira has been training with Rovers since last week and McCann says he will remain open minded about the 20-year-old's future.
Rovers will field a strong side in a friendly at Deeping Rangers tonight with much of the side that featured against Birmingham City last Friday playing in the game.
James Coppinger is set to play around 60 minutes as he continues his recovery from an ankle injury.