Early career Giagos made his professional mixed martial arts debut in 2009 competing as a
lightweight primarily in regional promotions across
California. He was able to compile a record of 10–2, including winning the
RFA Lightweight Championship on August 22, 2014 with a TKO stoppage of
Dakota Cochrane. On the heels of that victory, Giagos signed with the
UFC in the fall of 2014.
Ultimate Fighting Championship Giagos made his promotional debut against
Gilbert Burns on October 25, 2014 at
UFC 179. He lost the bout via submission in the first round. Giagos faced Jorge de Oliveira on March 21, 2015 at
UFC Fight Night 62. Giagos won the fight via submission in the first round. Giagos faced
Chris Wade on June 6, 2015 at
UFC Fight Night 68. He lost the fight by unanimous decision and was subsequently released from the promotion.
Absolute Championship Berkut He made his debut in Russia promotion against Alexandre Pimentel of Brazil at
ACB 51: Silva vs. Torgeson on January 13, 2017. He won the fight unanimous decision. In the second match he will make fight against Shamil Nikaev at
ACB 71: Yan vs. Mattos on September 30, 2017. He lost the back-and-forth fight by split decision.
Return to UFC On the heels of a 4–2 run on the regional circuit, Giagos made his return to the promotion against
Charles Oliveira on September 22, 2018 at
UFC Fight Night 137. He lost the fight via a submission in the second round. “I felt like when I came in the Oliveira fight, I was actually performing very well. I was actually really excited with my performance. I wish I opened up a little more. But, I was a little nervous of the takedown. This guy’s jiu jitsu is just next level, he holds the most submissions. I felt like I was doing really well. Everyone had me winning the first round." Giagos said of his performance after the fight. Giagos faced
Mizuto Hirota on December 2, 2018 at
UFC Fight Night 142. He won the fight via unanimous decision. Giagos faced
Damir Hadžović on June 1, 2019 at
UFC Fight Night 153. He won the fight via unanimous decision. Giagos faced
Drakkar Klose on August 17, 2019 at
UFC 241. He lost the back-and-forth fight via unanimous decision. Giagos was expected to face
Alan Patrick on
April 25, 2020. However, he was pulled from the fight citing injury and he was replaced by
Frank Camacho. Giagos replaced
Rick Glenn and faced Carlton Minus at
UFC Fight Night: Thompson vs. Neal on December 19, 2020. Giagos won the fight via unanimous decision. Giagos was scheduled to face
Joel Álvarez on May 15, 2021 at
UFC 262. However, Álvarez was removed from the bout in early May due to alleged
visa issues that restricted his travel. Giagos faced returning veteran
Sean Soriano. He won the bout via D'arce choke in the second round. This win earned Giagos the
Performance of the Night bonus award. Giagos faced
Arman Tsarukyan on September 18, 2021 at
UFC Fight Night 192. He lost the fight via technical knockout in round one. Giagos faced
Thiago Moisés at
UFC on ESPN 38 on June 25, 2022. He lost the fight via a rear-naked choke submission in the first round. Giagos was scheduled to face
Benoît Saint-Denis on September 3, 2022 at
UFC Fight Night 209. However, Giagos pulled out in early August after severing a tendon of his little finger during a domestic accident. Giagos faced
Ricky Glenn on April 22, 2023, at
UFC Fight Night 222. He won the fight by technical knockout in the first round. This performance earned Giagos his second
Performance Of The Night award. Giagos faced
Daniel Zellhuber on September 16, 2023, at
UFC Fight Night 227. He lost the fight via an anaconda choke submission in round two. Giagos faced
Ignacio Bahamondes on April 6, 2024, at
UFC Fight Night 240. He lost in the first round as a result of a head kick knockout. On October 10, 2024, it was reported that Giagos was removed from the UFC roster. ==Personal life==