The striker was handed a start as he had been in the original tie - a 2-2 draw at Moss Rose - 10 days earlier, but those are the only times Davies has featured in the Trotters' first XI in the last seven games, with his involvement in the Barclays Premier League during that time restricted to substitute appearances.
Coyle acknowledges it has been a frustrating period for the 34-year-old and was keen to praise Davies for his efforts in the match, saying: "As a striker, it is always important to score goals - I can vouch for that, I think I scored 297 myself."
He added: "It is always nice to be in amongst the goals because it breeds confidence, and I think Kevin certainly enjoyed it. But it is about more than just goals in terms of what he brings to the team, and I think he did that, particularly in the first half.
"He was winning headers, he was bringing us up the pitch and it looked as if he had that zest and enthusiasm about him, which will augur well and help us in the second half of the season."
There has been talk recently of Davies, who is in his ninth season with Bolton, potentially moving on, but Coyle has stressed the former Southampton man remains very much a part of his plans.
"He is our captain, he is an integral part of the club and nothing changes in that," Coyle said.
"He will have been disappointed of course - as one or two others will have been - not to have been in the starting line-up of late, but we have changed the system and David Ngog has been playing terrifically in that lone striker role.
"Sometimes you have to be patient, but when your chance comes, you have to do your utmost to say 'here I am, I want to be playing in the team' and one or two did that."
Davies broke the deadlock with little more than 30 seconds gone before Martin Petrov then doubled Bolton's advantage in the 26th minute.