Early career Clements made his professional MMA debut in June 2005, and fought primarily in his native Canada. In Clements' third fight, opponent
Lautaro Tucas charged across the ring at the opening bell with his hands down and was knocked completely out by a right hand from Clements, who had time to deliver a few punches to Tucas' unconscious body before the referee stopped the fight at 3 seconds of the first round, setting a record for the fastest knockout in MMA history. Clements amassed a record of 10-4 with knockout wins over
UFC veterans
Rich Clementi and
Jonathan Goulet before joining the
UFC himself in 2012.
Ultimate Fighting Championship Clements made his UFC debut against
Keith Wisniewski on April 21, 2012 at
UFC 145. He won the fight via split decision. Clements was expected to face
Siyar Bahadurzada on July 21, 2012 at
UFC 149, replacing an injured
Thiago Alves, however, on June 30, Bahadurzada was forced out of the fight. He was replaced by
Matthew Riddle. Clements lost the fight via arm-triangle choke in the third round. However, on October 20, 2012, it was revealed that Riddle has tested positive for a banned substance (marijuana) and the result was overturned and changed to a No Contest. Clements next fought
Stephen Thompson on September 21, 2013 at
UFC 165. He lost the fight via knockout in the second round. Clements faced Vik Grujic on November 8, 2014 at
UFC Fight Night 55. Clements won the fight via TKO in the first round. Clements faced
Nordine Taleb on April 25, 2015 at
UFC 186 after Taleb's original opponent,
Cláudio Silva, broke his foot. Clements lost the fight by unanimous decision and was subsequently released from the promotion. ==Mixed martial arts record==