M-1 Global On February 28, 2014, Delija made his M-1 Global debut in the main event of M-1 Challenge 45 against Estonian Denis Smoldarev and lost via submission (keylock). On September 20, 2015, Delija faced Marcin Tybura at M-1 Challenge 61 for the M-1 Global Heavyweight Championship and lost after he suffered a horrible open fracture of his
tibia. Delija had two surgeries on his leg and after the second surgery, he got infected by
hospital bacteria.
RIZIN Three years after injury, Delija made his comeback in the sport on May 6, 2018, in Fukoka, Japan at RIZIN 10 against Ricardo Prasel and won by unanimous decision.
KSW On November 9, 2019, Delija made his debut for
Konfrontacji Sztuk Walki, in which he TKOed Englishman –
Oli Thompson in the second round.
Ultimate Fighting Championship (UFC) (2020) Delija was scheduled to make his
UFC debut at
UFC Fight Night: Ortega vs. Korean Zombie on October 17, 2020, in
Abu Dhabi against
Ciryl Gane. The bout was cancelled due to Delijas' active contract with
Professional Fighters League.
Professional Fighters League (PFL) On February 9, 2021, it was announced that Delija would be part of the PFL heavyweight roster for 2021 season. Delija opened the PFL 2021 season on May 6 in
New Jersey at
PFL 3 against Bruno Cappelozza and lost via TKO in first round. On June 25, Delija defeated Chandler Cole via TKO in first round at
PFL 6 and secured place in the PFL Playoffs. On August 19, Delija defeated Denis Goltsov via unanimous decision at
PFL 8 and advanced to the PFL Playoff finals. On October 27, Delija faced Bruno Cappelozza in the PFL finals at
PFL 10 and lost in five round bout via unanimous decision. Delijas PFL 2022 season campaign started with a KO victory over Matheus Scheffel on April 28 at
PFL 2. On June 24, Delija defeated Shelton Graves via unanimous decision and secured his place in the 2022 PFL Playoffs. In the PFL Playoff semi-finals, Delija faced
Renan Ferreira at
PFL 8 and won by TKO in first round and advanced to the finals. In the finals, Delija was set to face Scheffel, whom he already defeated in first round of tournament and this time was no different. Delija knocked him out in the first round, becoming the PFL 2022 Heavyweight champion and earning the 1 million dollar prize in the process. Delija faced
Maurice Greene on June 16, 2023 at
PFL 5. He won the bout via unanimous decision. Delija faced
Valentin Moldavsky at
PFL 1 on April 4, 2024. He lost the bout by technical knockout in the first round. Delija was scheduled to face
Vadim Nemkov on January 25, 2025 at
Bellator Champions Series 6 (also marketed as
PFL Road to Dubai: Champions Series), but Delija withdrew for unknown reasons and was replaced by
Corey Anderson.
Fight Nation Championship On March 7, 2025, it was announced that Delija had left PFL and signed with leading Croatian promotion Fight Nation Championship. In his promotional debut, Delija faced
Yorgan de Castro on April 12, 2025, at FNC 22. He won the fight via technical knockout in round one. Delija made his UFC debut against
Marcin Tybura in a rematch on September 6, 2025 at
UFC Fight Night 258. He won the fight by knockout in the first round. This fight earned him his first
Performance of the Night award. Delija faced
Waldo Cortes-Acosta on November 1, 2025, at
UFC Fight Night 263. In the first round, the fight was briefly halted due to an eye poke, initially resulting in a mistaken technical knockout win for Delija. After video review, the bout resumed, and Delija lost shortly after by knockout. Delija was scheduled to face
Serghei Spivac on February 1, 2026 at
UFC 325. However, the bout was moved to February 21, 2026 at
UFC Fight Night 267 for unknown reasons. Delija lost the fight by unanimous decision. Delija is scheduled to face
Johnny Walker at
UFC Fight Night 282. == Championships and accomplishments ==