Trailing Gaziantep by four points in the table, Sivasspor find themselves in the relegation zone, owing largely to their poor away record this season.
Match preview
Gaziantep booked their place in the quarter-finals of the Turkish Cup with a penalty shootout victory over Konyaspor on Thursday, following ex-Manchester United forward Mame Biram Diouf's last-gasp equaliser for the visitors.
Both sides scored their first six penalties before Ugurcan Yazgili missed Konyaspor's seventh, leaving Mustafa Eskihellac to convert the winning spot-kick.
Reaching the Turkish Cup quarter-finals is a commendable achievement for Gaziantep, who managed to reach the last eight on just one occasion in the past 11 seasons, but there is no hiding the fact that Erol Bulut's side are struggling in the league.
Indeed, Gaziantep have failed to win any of their previous eight Super Lig games, recording four draws and four losses, with their last league victory coming all the way back on November 20.
It is also worth noting that GFK have failed to taste victory in their past five home matches in the Super Lig, while Bulut's men have won only two of their eight home league clashes this term.
Like Gaziantep, Sivasspor punched their ticket to the quarter-finals of the Turkish Cup earlier this week, claiming a comfortable 3-0 win against third-tier opposition as Hakan Arslan bagged a brace.
Regardless of Tuesday's triumph, Sivasspor cannot afford to rest on their laurels, as they currently sit third from bottom in the Turkish Super Lig table having won just three of their 18 matches this season.
After losing 2-1 to Galatasaray in late December, Riza Calimbay's side played out a 2-2 draw with Konyaspor before suffering a 4-1 thrashing at the hands of Kayserispor, meaning they have taken a solitary point from their previous three league outings.
Worse still, the Braves have only managed to win one of their last eight Super Lig clashes, suffering five defeats in the process, with two victories coming in their eight away league games this term.
Veteran winger Max Gradel has bagged eight goals and five assists across all competitions this season, while Dia Saba has contributed six goals and seven assists, so Calimbay will be hoping that his productive duo can rise to the occasion on Sunday.
Gaziantep Turkish Super Lig form:
D
D
L
D
D
L
Sivasspor Turkish Super Lig form:
L
D
W
L
D
L
Team News
Gaziantep will be without the suspended Angelo Sagal on Sunday, as the Chilean winger picked up a red card in last weekend's 2-1 defeat to Fenerbahce, while Abdulkadir Parmak, Ertugrul Ersoy and Stelios Kitsiou are expected to miss out due to injury.
Bulut made a host of changes to his starting XI for Thursday's Turkish Cup triumph over Konyaspor, so the German boss should revert back to a more familiar lineup this weekend.
For the visitors, Clinton N'Jie looks set to miss Sunday's clash after the former Tottenham Hotspur winger picked up a thigh injury last time out, with Erdogan Yesilyurt poised to take his place in the starting XI.
With Leke James, Aaron Appindangoye, Murat Paluli, Mustapha Yatabre and Karol Angielski also sidelined due to injury, Sivasspor will head to Gaziantep with a depleted squad.
Gaziantep possible starting lineup:
Guvenc; Artan, Tosca, Djilobodji, Pehlivan; Merkel, Jevtovic; Eskihellac, Maxim, Markovic; Figueiredo
Sivasspor possible starting lineup:
Vural; Yalcin, Goutas, Osmanpasa, Erdal; Ulvsted, Keita, Charisis; Yesilyurt, Musa, Gradel
We say: Gaziantep 2-1 Sivasspor
Although Gaziantep are without a league victory in eight games, this clash provides Bulut's men with the ideal opportunity to return to winning ways, given that Sivasspor are languishing in the relegation zone.