History informs us that clubs leading the Championship at this stage have been promoted in each of the last five seasons, and Cardiff looked the part, when they fought back from a goal down to stretch their lead at the top of the table to five points.
It was the Welsh team's 11th win in 12 home games and, coming just five days after victory at Leicester, the result further shortens the odds against them gaining promotion to the top tier for the first time since 1960. It was also revenge for their 3-2 defeat at Selhurst Park in September, when they led 2-0 only for Glenn Murray to destroy them with a hat-trick.
Palace were the better side in the first half, and took a deserved early lead through the combative Mile Jedinak, but Cardiff hit back decisively with goals from Craig Noone and substitute Aron Gunnarsson. Craig Bellamy was not on the score sheet on this occasion, but his tireless running and expert delivery to set up both goals made him the man of the match.
Palace, third at kick-off, have only three points to show from their last four games, but for a long time they were the better team, quicker in thought and deed. The Eagles soared after only three minutes when Jedinak, at the near post, met Owen Garvan's corner from the right and steered his shot inside the far upright.
At this stage the much-coveted Wilfried Zaha had the look of a match winner. When he cut inside from the left and let fly with a curling shot it had David Marshall beaten and he looked much relieved to see the ball bounce out off his crossbar. From the rebound Murray hit the goalkeeper's left-hand post.
After 24 one-sided minutes Bellamy at last stirred a stunned home crowd when he had a close-range shot diverted behind. Cardiff dug deep in spirited and muscular fashion, equalising in the 44th minute when Bellamy accelerated to the byline on the left before crossing for Noone to drive the ball into the roof of the net from a central position.
The second half was a reverse of the first, with Cardiff dominant and Bellamy, shooting right to left, demanded a notable save from Julián Speroni. The turnaround was complete in the 73rd minute when, from Bellamy's corner on the left, Gunnarsson headed home via the crossbar. Whittingham then struck the bar with a free-kick from 25 yards and Rudy Gestede fired over with almost the last kick of the match.
Malky Mackay, the Cardiff manager, said: "They started well and it took us half an hour to get into the game, but I thought we were excellent in the second half when we can grind teams down with our extra fitness."
Defeat was bitter for Palace's Ian Holloway: "We started well and ended terribly. I was bitterly disappointed with the last 15 minutes, because if either team looked like scoring again it was Cardiff."