But it appears some sections of the Bulgarian media did not agree the game was marred by racism.
"This is absolutely not true," the unnamed journalist said during Southgate's post-match press conference.
What difficult situation and circumstances what are you talking about? It's an exaggeration. The game was so friendly.
Bulgaria head coach Krasimir Balakov insisted he was not aware of any racist abuse and hit out at England supporters for their own behaviour.
Balakov claims he 'didn't hear racist chanting'
"I personally did not hear the chanting," Balakov said.
"I saw the referee stopped the game but I also have to say the behaviour was also not only on behalf of the Bulgarian 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."
HENDERSON - BALAKOV NEEDS TO APOLOGISE
"I had a few words with the manager [during the game]. It wasn't acceptable – something needs to be done," the Liverpool captain told Sky Sports News.
"He needs to apologise now, really, on behalf of the team and the fans. He knows what was going on. He was asking me what the problem was.
"When I told him he knew what was going on, it was baffling how he didn't, really. Hopefully he looks back and apologises because anyone watching that game would be disgusted really."
RASHFORD PRAISES CAPTAIN POPOV'S 'COURAGE'
With the toxic game on the verge of being abandoned, Bulgaria's captain Ivelin Popov was filmed at the half-time break speaking to supporters near the players' tunnel to try and calm them down.
Marcus Rashford, who was subjected to racist abuse on a miserable evening in Sofia, took to social media to praise the efforts of Popov.
He wrote: "Also been told what the Bulgaria captain did at half-time. To stand alone and do the right thing takes courage and acts like that shouldn’t go unnoticed. #NoToRacism"