"I know Erick has a lot of good strikes, but I believe it was very good luck to have won in the second round like that," Kim said via translator after the event, which took place at Jose Correa Arena in Barueri, Sao Paulo, Brazil.
Kim vs. Silva aired on the FOX Sports 1-televised main card following prelims on the same channel.
The stroke of luck earned Kim an extra $50,000 in pay for "Knockout of the Night."
"I trained a lot of grappling," he said. "I know Erick has a lot of good strikes, but I believe it was very good luck to have won in the second round like that."
Also completely unplanned for Kim was a grab of the fence after Silva attempted to lift and slam him to the canvas just prior to the fight-ending sequence.
On social media, many fans took note of the illegal maneuver despite several fence grabs from Silva (15-4 MMA, 3-3 UFC) as Kim (18-2-1 MMA, 9-2 UFC) attempted to take his chief weapon – striking – away earlier in the fight.
For his part, Kim was contrite about his lapse.
"I don't remember, but if I had the fence, I apologize," he told MMAjunkie.com.
Silva initially resisted the Korean's attempts to get the fight to the mat and landed several heavy strikes, which prompted extended bouts of clinching.
"I tried to tie up my opponent a little bit, and I knew I was going to take a lot of punches," Kim said. "So I tried to counter the attack.
"Erick Silva was very strong. He started very aggressive, and it was a war. I needed to fight against him, or I was going to lose. So I was trying to make Erick lose his strength. But I think it was luck (that I finished the fight by knockout)."