UEFA confirmed yesterday their match delegate at the San Siro received a complaint immediately after the game, which ended in a 2-2 draw, to leave Hector Cuper's side with the advantage when Group A comes to a head next Wednesday.
LuaLua was introduced as an 82nd minute replacement for Nolberto Solano and locked horns with Vieri, scorer of the first of Inter's two equalisers on the night, as the visitors defended a free-kick in the dying moments of the game.
Several players were involved in an untidy scuffle just outside the Newcastle box, but Portuguese referee Lucilio Cardoso Cortez Batista eventually restored order.
UEFA's disciplinary chiefs will now launch an investigation into claims that Vieri racially abused the Congolese international.
"UEFA is to investigate allegations that Internazionale FC's Italian international striker Christian Vieri made racist remarks to Newcastle United FC's Lomana LuaLua during last night's UEFA Champions League match in Milan," read a statement on www.uefa.com.
"European football's governing body said Newcastle had made an official complaint to the UEFA delegate at the match, alleging that Vieri, who scored Inter's first goal in a 2-2 draw, had made comments to LuaLua two minutes before the end of the game.
"UEFA said that it would instigate disciplinary proceedings and investigate the alleged offence, and that a decision would most likely be taken on March 21, with any appeal dealt with on April 3 or 4."
LuaLua was cautioned for his part in the incident, while Vieri had earlier picked up his third yellow card in this season's competition which will rule him out of his side's crucial trip to Bayer Leverkusen next week.
United's claims come after LuaLua's team-mate Titus Bramble was taunted with racist chants by Inter fans, and a lighted flare was thrown into the massed ranks of Newcastle supporters in the stadium.
Magpies boss Sir Bobby Robson was asked about the abuse Bramble received and the Toon Army's repeated accusations of cheating by the Italians in the post-match press conference. Although he admitted he had heard neither, he did not mention the complaint against Vieri.
"To be honest and I mean this sincerely I was not too conscious or aware of anything like that taking place," he said. "I was absorbed in the game. I have heard things being said, but I was not a witness to that and I wouldn't want to comment on that situation."
It is not the first time UEFA's disciplinary regime has been needed to deal with these two sides this season.
Craig Bellamy was sent off four minutes into the first game between the sides at St James' Park in November.
To make matters worse, skipper Alan Shearer, who scored both his side's goals last night, was later convicted on video evidence of elbowing Fabio Cannavaro later in the same game and was handed a two-match suspension to rub salt into the wounds of a 4-1 defeat.