Saturday's 3 - 0 win over Nottingham Forest coupled with Watford's 3 - 2 defeat at Peterborough saw a six point swing in the the number of points required and leaves the Bluebirds needing just one point to secure promotion and 7 points to win the title.
A draw at home to Charlton on Tuesday will be enough to bring top flight football to Cardiff for the first time since the club were relegated from the old First Division in 1962.
City are 6 points ahead of Hull but crucially 12 points ahead of Watford with four games to play.
City took the lead against a Forest side who were physical from the start. The opening goal came when the impressive Kim tricked a defender with a clever switch and was then obstructed. Bellamy took the free kick for Helguson to steal in at the back post for a a free header.
Before half time Forest were down to 10 men when Henderson caught Helguson with a raised arm. There were no complaints from Forest manager Billy Davies afterwards and from that moment on there was only going to be one winner.
Helguson didn't start the second half. Rudy Gestede came off the bench and scored twice from powerful headers to give City what turned out to be an easy victory. Forest had little atacking intent as they tried to keep the score respectable. On another day City could have had five or six.
With news coming through that Watford were 3 - 0 down at one stage at Peterborough the atmosphere was rocking in the CCS.
There was a record crowd of 26588 (inc 2000 demoralised Forest fans) to witness City position themselves for the inevitable jump into the Premier League.
Roll on Tuesday night and hopefully a promotion party.