The Cheshire side have finished the season strongly picking up four wins in the last six weeks, but it was not enough to stave off the inevitable particularly as Wednesday maintained their form even though David Vaughan struck a terrific 25-yard goal early in the second half.
When news seeped through that the Owls were winning at the Withdean Stadium, the home crowd were preparing for the inevitable.
Jason Koumas' equally stunning curler from a similar distance to his fellow countryman's effort just rubbed salt into the wound.
But Crewe at least went out fighting and they were the better side in the second period.
Both sides seemed to be suffering from exhaustion in an indistinguishable first half which was devoid of goalmouth action.
Steven Thompson dragged a shot wide for the visitors early on and Gareth Taylor's screaming effort from 20 yards took a deflection and veered wide of the Cardiff goal as Crewe looked for an early break.
Koumas lofted a free-kick over and also saved his side at the other end when he cleared a Steve Foster header from a corner off the line.
Crewe finally broke through in the 58th minute when Vaughan picked up a Taylor pass and hit an unstoppable shot into the top corner past Neil Alexander.
But fellow Welsh international Koumas was equally dangerous from long range and he forced home keeper Ross Turnbull to make a low save with a stinging 20-yard drive shortly afterwards.
Steve Jones should have given Crewe the cushion of a two-goal lead when Vaughan played him through on the left of the box, but the Northern Ireland international screwed his effort wide and Koumas made the Alex pay with a brilliant right-footed effort to level the scores up with 15 minutes left.