Gallagher struck in the 2-0 FA Cup win over Yeovil Town.
"I was very pleased for him," Davis said. "Sam's impressed me since he's come into the first team squad and he always seems to squeeze one past me in training which I've reminded him to cut that back a little bit.
"He took his goal very well and not just his goal, his all-round game as well.
"He was good when he came on and it was good for him, and had I not been at the other end of the field I might have gone up to the middle of the field and shook his hand.
"We've got a manager that wants these guys to come through and play, and be involved.
"Secondly, they're involved in training every day and when you step into the first team it can be a bit of an eye opener for some of the youngsters to step up to the pace as quick as they can. Sam and Harry [Reed] have certainly done that and got their rewards again."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball