Jesus Perez focused on Adam Lallana's performance in Southampton's FA Cup third-round win over Burnley rather than discussing the issue with referee Mark Clattenburg.
Southampton have refused to accept the Professional Game Match Officials' decision to rule out action against Clattenburg following allegations the official verbally abused Lallana in last weekend's 2-1 defeat at Everton.
It has led to talk of a possible appeal to the Football Association and resulted in Lallana featuring prominently on the back pages of newspapers on Saturday.
However, it was a subject assistant Perez, speaking instead of manager Mauricio Pochettino, refused to talk about after the 4-3 third-round win over Burnley.
The Spaniard said he did not have "the authority to talk about it" and that it was a "situation for the club", although he was more forthcoming on Lallana's impact after his goal from distance proved the difference at St Mary's.
Perez said: "I think everyone can see Adam Lallana this season and every single minute he is on the pitch he tries to do his best and is always doing great, great things.
"It's no surprise for me when Adam Lallana on the pitch is doing things and goals like he did.
"I think it (the Clattenburg situation) hasn't affected him. We are professionals.
"When you are in this business you have to be aware of everything and you have to stay away from the pressure of some things around football and just focus on being fit and being mentally ready to play.
"He played like the other players of the squad with the best mentality at the end of a tough period where it's difficult to keep a strong mentality because fatigue is not only physical but also mental - and it was important for us to be in the next round."
Southampton had let slip a 2-0 lead before goals from Jay Rodriguez and Lallana secured the win, with Kevin Long's late effort merely a consolation.
"It was a strange game but you know in the cup game everything is possible because the teams are playing without pressure," Perez added.
"Sometimes one of the sides is clinical and the other not so much and I think that was the case.
"The most important thing is stay in the next round, especially when you play a cup game at the end of a tough period like Christmas was for us - and I'm just happy for that."
Progress was a relief for Southampton after a match that left Burnley manager Sean Dyche proud.
"If there is such a thing as losing a game the right way, then that is it," he said.
"Three of their scorers are England players and the other is worth £2.5million, so that shows a measure of the two clubs.
"But performance-wise we were excellent. We played with no fear, very good football and were very attack-minded.
"I think their players came off thinking 'wow, we could have easily got turned over'. They brought on two England internationals. That shows the strength in depth they have. I was going to bring on my assistant."