The Mali international powered his team to victory at the New Sivas 4 Eylul Stadium with his first-half strike that moved them to third in the table
Mustapha Yatabare scored the only goal as Sivasspor pipped Denizlispor 1-0 in Monday's Turkish Super Lig match but Ogenyi Onazi suffered an injury in the encounter.
Yatabare broke the deadlock just before the half-time, to take his league tally to 12 goals after 26 appearances so far this season.
The Mali international was in action for 70 minutes before he was replaced by Ivory Coast's Arouna Kone while Onazi was introduced just after the interval, but he could only manage 13 minutes of action before he was replaced due to injury by Cameroon's Marc Mbamba in the 59th minute.
The triumph moved Sivasspor to third in the Turkish top-flight standings with four points behind leaders Trabzonspor while Denizlispor dropped to 11th with 31 points after 27 matches.
Following his recovery from an Achilles tendon rupture that ruled him out of action for the most part of the 2018-19 season, Onazi joined the Roosters on a free transfer in January after struggling for playing time at Trabzonspor.
The Nigeria international has played eight matches so far this term, including his seven league appearances.
Meanwhile, Yatabare has proven to be Sivasspor's main threat in front of goal this season with his tally of 14 goals after 30 games across all competitions.
The France-born striker has played 32 matches for Mali, and he has scored five goals since his debut outing for the West African country in 2009.
The 34-year-old is joined by Mali goalkeeper and his compatriot Mamadou Samassa in Riza Calimbay's side as they aim for a European spot this season.
On the international scene, Onazi played for the Nigeria U17 and U20 teams at the 2009 Fifa U-`7 World Cup and 2011 Fifa U-10 World Cup before making his international debut for the Super Eagles in 2012.
The 27-year-old has made 52 appearances for the three-time African champions so far and he broke his duck during an international friendly game against Venezuela eight years ago in Florida.
On Sunday, Yatabare will be hoping to help Sivasspor maintain their fine form when they visit Konyaspor on June 21, however, Onazi will be looking to be available in time for Denizlispor's next league match against Besiktas on Saturday.