City saw off Peterborough 3-0 at the Coventry Building Society Arena on Friday night as Gyokeres' second-half double quickly followed Gustavo Hamer's opener.
"He's gleaming from belief," said Robins. " I said from when he came in he was absolutely brilliant, everything he hit was going in the net until he had a bit of a lull in pre-season.
"He was unlucky in the first half when he dragged his shot, but I'm really pleased with the movement.
"He looked like he was running on empty towards the end and there's no disgrace in that, he worked his socks off and he's got his goals. He was disappointed that I took him off because he was talking about his third one.
"I gave him his chance, he didn't get it, now get off!"
Coventry's three goals came in eight second-half minutes after the home side struggled to break down Posh in the opening 45.
Brazilian midfielder Hamer broke the visiting side's resistance by scoring his first goal since January after a free-flowing Coventry counter-attack in which he was at the right place at the right time to tuck home.
Once ahead, the home side raced into a 3-0 lead as Gyokeres got on the end of Todd Kane's perfect whipped cross before a stroke of luck saw his deflected effort loop over David Cornell in the Peterborough goal.
Robins added: "We found it difficult to get our noses in front, but from then on we really grew in stature and took the game away from them.
"I thought it was nothing less than we deserved, the performance was brilliant, the atmosphere was electric and it was a brilliant evening's work.
"It was a difficult game, I think they've given us a stern test. I thought we were decent in the first half and we had a lot of the ball, got into dangerous positions but just lacked a bit of quality at the end."
Peterborough manager Darren Ferguson bemoaned his side's mentality as their second-half collapse sealed a fifth defeat in as many away games this season.
"We concede, we collapse," said a despondent Ferguson. "It's another disappointing away defeat, another very similar away defeat. We concede, we collapse.
"Something has to change dramatically here because this has happened four times now.
"In the first half I didn't think we played with enough belief in the final third attacking-wise, but we needed to do more to win the game, we didn't come for a 0-0, we wanted to win the game.
"It's clear as day the problem, we conceded three goals in seven minutes. Seven minutes before that you're thinking OK you're in the game, it's very tight, seven minutes later the game is over and you're worried that it could be an absolute pasting.
"Some of them need to prove me wrong because I'm really, really not happy with that, I can't stand watching that again.
"We need to be tougher, it's not about ability, it's about being mentally tough and at the moment clearly we're too soft."