The Nailers had trailed 1-0 at the break before turning it around with a gusty second 45 minutes.
“It shows what the team is about and what they are willing to do for this club,” said Grant.
“If they keep doing that then we will win more matches than we will lose.
“It was a hard-fought win, but we knew that would be the case. They were on a good run and have had a new manager come in.
“The conditions were going to be a leveller for everyone. We had a plan to set up and I thought we played ok in patches in the first half.
“We created chances, as did they. We had talked about how good their lad is at free-kicks and not giving daft fouls away. We did that and were behind, but it was hard to be too negative.
“At the break we just said we had to roll our sleeves up and if we want to win it more than them then we can do that.
“The second half was down to that, we wanted to win that match no matter what.
“We put our bodies on the line and those wins please me more than five and sixes.
"We reacted well when we fell behind and got our rewards. We missed Jonathan Margetts and it is great to have him back.
“He got through 45 mins last week and he changed the game. His fitness shone through as well as his quality.
"We will take confidence from this going into Ilkeston, it is first v second and we are both on a good run.
“We will train hard this week, but we are going to enjoy this win first because it is a sweet one.”
Belper fell behind on 44 minutes after Dan Collins fired home a rebound from a free kick.
Jonathan Margetts kept his cool from the spot on 55 minutes after Brodie Litchfield was fouled.
Loughborough were reduced to ten men three minutes later after Carl Sibson was red-carded for foul and abusive language.
Belper’s Tom Wilson was sent off on 73 minutes, before Margetts doubled his tally with a beautiful free-kick two minutes later.
Loughborough were reduced to nine men when Tom Norris was sent off in stoppage time.