KOCAELI, Turkiye (Interstat) — In a stunning upset to open the Süper Lig season, newly promoted Kocaelispor defeated Turkish powerhouse Galatasaray 1-0 on Sunday at a raucous Yıldız Entegre Kocaeli Stadyumu.

The result defied overwhelming pregame projections, handing Galatasaray a shocking defeat in its 2025-26 league opener. Data from Interstat gave Galatasaray a 91.30 percent probability to win, with its game simulator predicting a 2-1 victory for the visiting favorites. Instead, it was Kocaelispor, riding a solitary first-half goal from Daniel Agyei, who claimed all three points.

The match’s lone score arrived in the final minute of the first half, a pivotal strike that shifted the entire complexion of the contest. In the 45th minute, forward Daniel Agyei found the back of the net, capitalizing on a well-constructed play to send the home supporters into a frenzy.

The assist on the decisive goal was credited to defender Hrvoje Smolčić, whose long pass from the back line unlocked the Galatasaray defense. The buildup also involved a key contribution from midfielder Anfernee Dijksteel, who was also awarded an assist on the play, highlighting a fluid attacking move that caught the favored visitors off guard.

The first half was a physical and contentious affair, setting the stage for the upset. Galatasaray’s star substitute, Victor Osimhen, entered the match early and quickly found himself in the referee’s book, receiving a yellow card in the 28th minute for a forceful challenge. The cautions continued as Kocaelispor’s Dijksteel was shown a yellow card in the 38th minute. Just before the halftime whistle, Smolčić, the architect of the winning goal, was also booked in the 47th minute for his role in the ensuing celebrations or an immediate foul after the restart.

The goal and the flurry of yellow cards underscored a half where Kocaelispor’s aggressive and organized game plan effectively disrupted Galatasaray’s rhythm. The visitors, heavily favored based on pedigree and pregame analytics, struggled to impose their will against a disciplined and determined Kocaelispor side.

The second half saw Galatasaray pressing for an equalizer, but the Kocaelispor defense held firm, preserving the clean sheet and the historic victory. The final whistle confirmed one of the most surprising results of the young Süper Lig season, delivering a massive statement from the promoted club.

With the victory, Kocaelispor begins its top-flight campaign with a perfect record of one win and zero losses, a start that immediately establishes the team as a potential tough out in the league. The loss for Galatasaray is a significant early setback, leaving the Istanbul giants with a record of zero wins and one loss as they look to rebound from an unexpectedly poor start. The records for both teams are identical across all competitions for the new season.