Huracan fans demand ban for referee
The fans, some wearing the club's white and red colours and carrying banners, called for referee Gabriel Brazenas and linesman Ricardo Casas to be suspended for life.
Hard core supporters aimed fireworks at police manning barricades, raising the spectre of violence though it did not materialise, and one fan with a megaphone shouted out Brazenas's home address.
Huracan posted a statement on their official website on Wednesday asking for sanctions against the match officials.
Brazenas apologised in the media on Monday for errors he said he realised he had made during the match when he saw TV replays, including missing a foul on Huracan goalkeeper Gustavo Monzon in the build-up to Velez's winning goal seven minutes from the end.
Huracan, most neutrals' favourites, had needed only a draw to win the Clausura championship having begun the match as leaders one point ahead of Velez.
The fans say Huracan, who have a modest budget, have lost the chance of huge earnings as a result of not winning the title that would have qualified them for next year's Libertadores Cup, South America's club championship.