The 22-year old Japan international netted a hat-trick as Gamba recorded a 4-2 away win over Singapore Armed Forces in the Asian Champions League group stage and although Nishino was delighted, he did not want to compliment his goalscorer too much.
“Hirai has been starting this season and there is a lot expectation and pressure on him. Fortunately, he is living up to expectations,” he said.
“Hirai did score a hat-trick but promised me four goals yesterday. So I won't compliment him too much.
“Hirai has missed many chances in previous matches so yesterday he promised me four goals after training and we shook on it.”
Nishino admitted he was not all worried when the score was 1-1 at half-time as he believed his players were well in control of the contest and is now looking to push on after beginning their campaign undefeated after three matches.
“SAF started the match quite aggressively, especially their number seven (Ahmad Latiff), who was distributing the ball quite accurately, so I was expecting counter-attacks. We lost focus and that's when SAF score two goals,” added Nishino.
“During half-time, the players weren't nervous about the score being 1-1 because we knew we were controlling the game and playing well.
“The team system could have been improved and we could have passed the ball around more effectively, but we weren't nervous at all.
“We haven't had a good season. Now we will aim to keep winning and climbing up the table in the Champions League.”