The Spaniard came back from a set down to seal the match 6-7 (5), 6-2, 7-6 (2).
There were no breaks of serve in the first set and Roddick managed to maintain his cool in the tie-break that he took 7-5.
However, the Spaniard Ferrer, who has already qualified for the Barclays ATP World Tour Finals, stormed back winning the second set 6-2.
The third set went with serve again and despite Roddick saving a matchpoint at 4-5, it was Ferrer who clinched the set and the match.
Japan’s Kei Nishikori will be playing his first ever semifinal at a Masters event as he dismissed Alexandr Dolgopolov of Ukraine in straight sets 6-4, 6-3.
Nishikori is poised to make history on Monday as he will become the highest ever ranked Japanese tennis player in history.