Story, known for a grinding wrestling style, this time refused to play on the ground with Mulhern, a jiu-jitsu black belt. Instead, he let his hands fly. During an early barrage, he clipped Mulhern with a left cross, setting the tone for his performance.
About midway through, a left hand found its target, and Mulhern backed up while holding his eye. Sensing the opening, Story pounced and cornered his opponent against the cage, where he let loose with another flurry. A short left dropped Mulhern, and Story landed a few ground strikes before the referee stepped in to call for the finish.
"I've got the power harnessed inside me," Story said after the win. "We brought that out this training camp and wanted to display it. I've had a lot of fights kind of grueling, not really fan friendly. I wanted to come in here and put on a show."
After losing three of his last four fights, it was a must-win for Story, who is now 15-6. The victory was his first stoppage win in the octagon since a TKO over Dustin Hazelett in August 2010.
Mulhern, who was making his UFC debut after moving over from Strikeforce, fell to 18-3.