Hamza Hamzaoglu's men teed up the rest of the weekend's action at the top of the table by battling to a 3-2 win at Sivasspor on Saturday.
That victory put Gala a point clear of Besiktas at the summit, but Slaven Bilic's side, who travelled to Liverpool for the first leg of their UEFA Europa League last 32 tie on Thursday - fell to a 1-0 defeat at Eskishirspor.
Kaan Kanak handed the hosts an early lead, and Besiktas - without the influential Demba Ba through injury - were unable to find a way back.
Having seen Besiktas fail to reclaim their place at the summit, Gala will have watched with interest as Fenerbahce aimed to go top at home to Akhisar Belediyespor on Monday.
Guray Vural scored in the fifth minute to give Fener an early scare, before Raul Meireles restored parity with 41 minutes on the clock.
The match looked to be heading for a draw until Ricardo Vaz Te popped up in the 89th minute to snare a 2-1 victory, slipping two points behind the league leaders.
At the other end of the table, Kayseri Eciyesspor climbed out of the relegation zone with a 3-0 win against Konyaspor on Friday.
That result saw them go above Rizespor and Karabukspor, who picked up a 1-1 draw at Bursaspor and a 2-1 defeat at Mersin Idmanyurdu respectively.
Basement club Balikesirspor lost 1-0 at home to Genclebirligi.
Elsewhere, Istanbul Basaksehir registered a 1-0 win against, while Kasimpasa drew 1-1 with Trabzonspor.
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