City couldn't build on Sunday's fine win and it was Brighton who marched on with a 100% record.
Brighton were a much better team than Bristol City and made it difficult for Cardiff in the first half. Running too early saw Craig Makail Smith caught offside too often including once when he finished but the flag curtailed his celebrations.
Cardiff were playing their part but the clear cut chances were not coming and Brighton's steady play was rewarded by a lapse from Kevin McNaughton. His wayward crossfield pass fell to Brighton's Ashley Barnes who, unchallenged, beat Marshall from 25 yards.
A poor goal to give away and it introduced self inflicted pressure.
Brighton started killing time and their keeper was booked for stalling a goal kick. Cardiff looked to press more but without really harming the Brighton defence who then broke at breakneck speed through Mackail Smith and he danced around Mark Hudson before being pulled down for a penalty that Barnes converted.
The breakaway from a Cardiff attack to a Brighton penalty was just a few seconds. They were devastating on the break.
Into the last 10 minutes and Will Hoskins scored Brighton's third as they raced away again.
Cardiff had faint hope. A penalty, converted by Peter Whittingham (see pic), at the start of five mins injury time was followed by a Craig Conway miss in front of goal. Had that gone in to make it 2 - 3 we would have had a real grandstand finish.
The game petered out, by then half of the 23,000 crowd had gone and we have to wait another year at least to attempt to win our opening three league games. A feat we've never achieved.
Next up a trip to Burnely on Saturday.