Kelvin Gastelum earned the biggest win of his young career when he knocked out former UFC middleweight champion Michael Bisping in the first round of the main event of UFC Shanghai. It was Bisping's second fight in three weeks, as he dropped his middleweight title to Georges St. Pierre at UFC 217 on Nov. 4.

Gastelum landed a big left hand that floored Bisping and followed up with some ground-and-pound before the referee stepped in. After the fight, he said he's hoping to face interim middleweight champion Robert Whittaker in February at UFC 221.

This is the first time Bisping has lost back-to-back fights in his storied career. In his post-fight interview, he reiterated that he intends to call it a career on home soil in a retirement fight at UFC London on March 17.

Full results from the event can be found below:

- Kelvin Gastelum def. Michael Bisping via KO (punches) at 2:30 of Round 1

- Li Jingliang def. Zak Ottow via TKO (punches) at 2:57 of Round 1

- Wang Guan def. Alex Caceres via split decision (28-29, 29-28, 29-28)

- Alex Garcia def. Muslim Salikhov via submission (rear-naked choke) at 3:22 of Round 2

- Zabit Magomedsharipov def. Sheymon Moraes via submission (anaconda choke) at 4.30 of Round 3

- Kenan Song def. Bobby Nash via TKO (ground and pound) at 0:15 of Round 1

- Yan Ziaonan def. Kailian Curran via unanimous decision (29-28, 29-28, 30-27)

- Yadong Song def. Bharat Khandare via submission (front choke) at 4.16 of Round 1

- Shamil Abdurakhimov def. Chase Shermon via knockout (punch) at 1.24 of Round 1

- Gina Mazany def. Yanan Wu via unanimous decision (30-27, 30-27, 30-27)

- Rolando Dy def. Wu Lijiburen via unanimous decision (30-27, 29-28, 30-27)

- Cyril Asker def. Yaozong Hu via submission (rear-naked choke) at 2.33 of Round 2