Albion thought they could have had a penalty at Birmingham – seconds before the home team scored.
Craig Mackail-Smith tumbled under pressure from former Seagulls defender Grant Hall.
But play was waved on and the resulting counter-raid led to Wes Thomas heading the only goal.
There were only muted appeals at the time of the incident.
Initial reaction from the media area in the main stand is that it WASN'T a spot kick.
Albion reviewed video footage of the clash after the match and felt Hall should have been penalised.
Either way, Hyypia did allow the incident to colour his judgement of his side's performance
- Video - Cardiff keeper denies Albion
- Have your say - who was Albion's man of the match against Cardiff?
- Sami Hyypia backs keeper David Stockdale
- Sorry fans! Honest Stockdale holds his hands up for 'bad decision'
- Birthday boy Bruno was going for goal