Bulgaria head coach Krasimir Balakov claimed not to have heard racist chanting during his team's 6-0 loss to England in Sofia and accused the travelling supporters of 'unacceptable' behaviour.
But the contest was sullied by abuse directed towards some of the travelling players, which was reported to the match officials and resulted in two delays to the action before half-time.
Before the match, Balakov accused England of having a bigger problem with racism in football than his own country, and he once again sought to share the blame after the widely condemned scenes that stained Monday's match.
"I personally did not hear the chanting that you are most probably referring to. I saw that the referee stopped the game," he told ITV.
"But I also have to say that the unacceptable behaviour was not only on behalf of the Bulgaria fans but also the English fans, who were whistling and shouting during the Bulgarian national anthem.
"During the second half they used words against our fans, which I find unacceptable."
Balakov said he felt an increased focus upon the potential of racist incidents before the game made them more likely, while he called for the abuse to be 'proven' despite audible monkey chants during the contest and the spectacle of some Bulgaria fans being ejected.
"We've had this problem ever since England were about to come to Bulgaria. All I've heard for three weeks is people talking about anything else but football," Balakov said.
"I don't think this was the proper manner to prepare and to play a football game. For three weeks, everyone was talking about one thing.
"If this turns out to be true, we are truly sorry and we as the Bulgarian national team and the Bulgarian Football Union are working very hard.
"Nobody wants to see this but let me tell you that this really has not happened in our games up until now. This happened now in the England game.
"If something can be proven then we are sorry but we cannot speak on behalf of some fans here."
Marcus Rashford opened the scoring for England and tweeted after the match to praise Bulgaria captain Ivelin Popov for remonstrating with supporters at half-time.
Popov's move was widely interpreted as a call for discriminatory chants to stop but Balakov told a post-match news conference he felt the Rostov midfielder was responding to complaints over a poor performance.
"I have no idea about this. If our captain spoke to the fans it is probably because they were unhappy about the way in which the team were performing," he added.
"The whole topic in the build-up to the game – the fans are emotional. You want me to say this and I have to say this, if something happened I'm sure it really was a small group of people who really were out of their minds because this is unacceptable… if it happened, of course."