The other time you're remembering it didn't really "fail". What you mean was CRS-1 during which's first stage flight an engine failed. One condition for the restart to put the secondary payload into orbit was a 99% success rate that the payload would end up above the Station. But due to the earlier engine failure the probability was 'only' 95% so the stage wasn't allowed to relight but it would have most likely worked.
As pointed out earlier by me they already did the restarting of the second stage before, at the COTS Demo Flight 1.
The Falcon 9 v1.0 maiden flight suffered a similar failure upon an attempted restart of the engine.