Nathan Cartman opened the scoring from the penalty spot, and then set up the second goal for the returning Kieran Weledji.
The win was sealed with a superb lob from super-sub James Cadman in the second half.
Greening said: "I was very impressed with how Kieran (Weledji) played after having been out injured for such a long time, but with Josh Barrett and Lewis Turner both out with slight knocks I had to put him in from the start and he did very well, especially in the first half. He is a very good option as he can play right-back centre-back and even centre-forward if needed!.
"They all played very well last night, defensively we were very strong and had a lot of composure and on the attacking front we also looked lively."
The former Manchester United and West Brom midfielder was quick to praise the impact of the returning keeper Ryan Whitley, who had only signed on loan from York City a few hours before kick-off on Friday.
He said: "Ryan is such a big imposing keeper and he came for everything, commanding his area, he made a big difference and this in turn gave the defence a lot more confidence and we were very strong in the air. We have been trying to bring him in for a while and it was great to get the deal over the line.
"The midfield also impressed on Friday, and Michael Coulson, Nathan Cartman and Nick Hutton, who had his best game for us, were all dangerous up front.
"I made it clear to the lads at the end though that as impressive as this was we need to make sure we play like that again on Saturday at Basford in the NPL opener, doing well in pre-season is okay but it is the league where it really mattes."
Boro open their NPL Premier Division campaign at Basford United on saturday August 14.