Rovers were much improved after the break and scored goals through debutant Alfie Beestin and Riccardo Calder to get their Checkatrade Trophy campaign off to an ideal start with a 2-0 win.
Ferguson said he wanted his side to be a bit less nice at Field Mill but was happy with the response.
"I thought second half we were good," he said.
"First half we did ok. I didn't think we played with enough zest in our game. It was a bit too nice for me.
"We spoke about that at half time. I expected more out of them to be honest which is a compliment. I could easily have gone in and said they had done fine.
"They had one header at the end and one shot. We were solid enough, certainly.
"We just needed more going forward. Second half they did that. I felt they we really good."
Ferguson named a particularly young team for the game with Reece Fielding and Liam Mandeville joining Beestin as teenage starters while Danny Amos, Will Longbottom and Joe Pugh came off the bench.
And the Rovers boss feels they justified him tipping them for successful careers.
He said: "For me, the future in terms of the players that played is bright.
"We've got a lot of young players but good ones.
"I said to them at the end they have to trust each other. They played a totally different system and it worked.
"It's not really about systems, it's about trusting each other.
"Once they got a bit more energy out wide and Matty Blair and Riccardo Calder started running their full backs a bit more, I thought we controlled the game.
"Two good goals. A debut goal for Alfie and Calder's first goal."