He was named Croatian K-1 Fighter of the Year in 2013 by a jury of experts made of Fight Channel members, kickboxing coaches and sports journalists.

He achieved stoppage victories against Andreas Peters in the quarterfinal and Renato Sini in the semifinal, before winning the tournament through a unanimous decision against Roman Kleibl in the final.

[9] In October 2014, Brestovac defeated Koos Wessels by unanimous decision, to qualify to the 2009 K-1 ColliZion Final Tournament.

[10] Brestovac scored knockouts of Mihaiţă Golescu in the quarterfinal and Coco Rus in the semifinal, before facing Roman Kleibl in the final.

He defeated Mighty Mo by a body kick KO in the semifinals, but lost the final bout against Ismael Londt by TKO, after the ringside doctor stopped the fight in the first round.

[13] After a TKO win against Mourad Bouzidi, in March 2012, Brestovac fought the first match, of what would be their trilogy, against Benjamin Adegbuyi.

Adegbuyi won the semifinal bout of the 2012 SUPERKOMBAT World Grand Prix III by unanimous decision.

[14] Brestovac was scheduled to fight Chinese giant Taishan in a non-tournament bout at the K-1 World Grand Prix 2012 Final in Zagreb, Croatia on March 15, 2013.

Returning to FFC, he scored a TKO win against Luca Panto, who suffered an arm injury in the first round.

[39] Following his first loss in over three years, Brestovac was scheduled to defend his NDC title against Fabrice Aurieng in November 2015.

[44] Brestovac snapped his losing streak with a second round head kick knockout of Banks.

[45] Brestovac participated in the 2016 Glory Heavyweight Contender tournament, being scheduled to fight Jahfarr Wilnis in the semifinals.

[46] He knocked Wilnis out with a head kick in the first round, and advanced to the finals, where he was to fight a rematch with Benjamin Adegbuyi.