Feral Druids. I cannot kill them.

In a recent 3v3 match, my opponents were also Triple DPS. A rogue, ret paladin, and a feral druid.

I killed both the rogue and the retribution paladin. I lost a single DK, the other 2 were at full health and the feral druid was also at full health.

No problem right? 2v1? Piece of cake? I lost. I was smashing him as hard as I could, but I could not overcome his frenzied regeneration and bear form.