Rangers manager Steven Gerrard has called for harsher sanctions after Glen Kamara was allegedly targeted by schoolchildren at Sparta Prague, while the player's lawyer has labelled UEFA "a disgrace".
Boos were audible when Kamara touched the ball, more than for any other Rangers player, as Sparta secured a 1-0 Europa League win.
The treatment of the midfielder came five months after Slavia Prague defender Ondrej Kudela was banned for 10 matches having been found guilty by UEFA of racist behaviour towards Kamara, who received a three-game ban himself for an alleged assault on the Czech player in the Ibrox tunnel.
Sparta's Letna Stadium was originally meant to be shut following a separate racist incident after Monaco's Aurelien Tchouameni was subjected to abuse from the stands last season, but UEFA agreed for Thursday's game to go ahead in front of mainly schoolchildren with some accompanying adults.
Kamara was sent off in the 74th minute, to huge cheers from the crowd, after receiving his second yellow card for an aerial challenge in what looked a harsh decision.
When asked about the jeers Kamara faced, Gerrard told a press conference on Thursday night: "During the game, I haven't been aware. I have obviously been focused on the game and the tactical changes that I was trying to think about to try and get us back in the game as we were trailing."
However, Gerrard confirmed on Friday he heard the booing when he watched the game again.
"I'm fully aware now, having watched the game back with audio on," he said. "I'm actually surprised that I wasn't aware of it during the game.
"I have spoken to Glen Kamara - that conversation will remain private. Glen's okay. I'm sure he's disappointed, just like myself. Now I think it's time for the authorities and the club to step in take that away from us so we can focus on the game on Sunday.
"There are hundreds of thousands and maybe more people frustrated because these things keep raising their head far too often. Unfortunately the punishment is not enough. I said last night there needs to be more done. It's the only way it's going to get eradicated because the punishments are nowhere near severe enough."
Gerrard also said "the wheels are already in motion" for Rangers to formally contact UEFA about the matter, while the organisation's disciplinary body is awaiting reports from match delegates before deciding whether to take any action.
"I've been told that Rangers are going to take it up with UEFA. I think those wheels are already in motion. I'll certainly be pushing to make sure that's the case," he added.
Kamara's lawyer: Let's be blunt, UEFA are a disgrace
Kamara's lawyer, Aamer Anwar, said Sparta Prague should be embarrassed by the behaviour of their supporters and that Thursday's scenes again highlighted Czech football's "deep-rooted problem with racism".
Speaking to Sky Sports News, Anwar also accused UEFA of not taking sufficient action against racism.
He said: "Let's be blunt, they (UEFA) are a disgrace. They fail to act on each and every occasion. They like to talk about respect - where was the respect for Glen Kamara? Where was the respect for Rangers' black players and every time any other black player goes onto the pitch to be abused in such a manner? This is their place of work.
"Glen Kamara, and no other player, should be subjected to such abuse every time they venture out."
Anwar released a statement on Thursday night criticising Sparta Prague and revealed he was then subjected to a number of racist messages on social media.
"When will UEFA say enough is enough?" he said. "There is no point in talking about respect, carrying banners and saying you're against racism.
"I'm sure Glen Kamara, his team-mates and Steven Gerrard do not want to be talking about racism. They want to be talking about the football."
Sky Sports News has contacted UEFA for a response.