Host Canada earned the silver in 4:09.137 and the United States finished the distant third in 4:14.081, after the judges reviewed the video replay and disqualifed South Korea for impeding.
Tania Vicent of Canada said they had planned to stay behind China and South Korea knowing uncomparable against the two.
"We knew the Chinese and Korean teams were fighting it out, so our tactic was to stay right behind them and take advantage of their mistakes. We got a record time for Canada, we can't do better than that," said Vicent.
It took a while at the side of the rink on Wednesday evening for the Chinese coach Li Yan to raise objection before the judges' decision set off huge arguments with the Korean coaches but jubilation from China and the other teams.
Involving four teams and 16 skaters in total, the relay started with Wang Meng in the lead and the Koreans bumped and jostled around the oval to overtake the position halfway.
It was not until the last few laps that South Korea's Kim Min Jung intended to block China's Sun, which resulted in the Korean team being disqualifed and the Chinese team being awarded the gold medal.
"She was trying to overtake me and she couldn't get through, so I guess that's how the collision happened," recalled Sun after the final. "I think the referee's decision is fair."
Kim, however, declined to admit her intension, and said: "I don't know what the reason is. I don't have any clue what the referee was saying. It doesn't make any sense at all."
Those South Korean flags held aloft proudly by Cho Ha Ri, Kim Min Jung, Lee Eun Byul and Park Seung Hi drooped when their disqualification was announced.
After the race, the Olympic broadcasting service showed that China's Zhang Hui came off the ice with a cut to the chin, raising the suspicion about her injury.
Wang Meng, however, explained to the media at the mixed zone that Zhang's cut was not gotten during the competition.
"It was an accident. We were celebrating after the referee's decision which disqualified the Korean team, and she was accidentally cut in the face by a blade," Wang said.