Guus Hiddink would not condemn the few Chelsea supporters who booed Eden Hazard during Wednesday's defeat to Paris Saint-Germain.
A small number of boos were audible when Hazard signalled to the bench and was replaced by Oscar during the second half of a 2-1 Stamford Bridge defeat that sealed Chelsea's Champions League exit.
The Belgian risked riling supporters by swapping shirts with Angel Di Maria as the players left the pitch at half-time in the second leg with the tie in the balance.
Hiddink last month told Hazard to keep his focus on Chelsea after the player gave an interview ahead of the first leg in which he said it would "be difficult to say no" if PSG or another Champions League contender came calling.
And asked about the shirt swap the Blues boss said: "I'm aware. It should not be done. But in some countries it's usual that you do it [at half-time] and not after the game.
"Maybe they're both used to doing that. Don't overvalue this issue."
Asked about the booing, he said: "Yes, they had the right to do what they think. You can express always your feelings."
Hazard will be assessed by Chelsea's medical staff on Thursday ahead of Saturday's FA Cup quarter-final at Everton.