Hamza Hamzaoglu's side claimed a 3-1 win over strugglers Kayseri Erciyesspor on Friday, with second-half goals from Aurelien Chedjou and Wesley Sneijder settling the clash after Bjorn Vleminckx had cancelled out Umut Bulut's early opener.
That put Gala four points ahead of Besiktas and five clear of Fenerbahce, and both their neighbours duly wilted under the pressure on Saturday.
A Ronald Vargas penalty seven minutes from time gave bottom club Balikesirspor a 2-2 draw at Besiktas, who then had defender Pedro Franco sent off in the second minute of injury time.
Meanwhile, Fener were left to settle for a 1-1 draw at Konyaspor - Egemen Korkmaz levelling for Ismail Kartal's side after May Mahlangu had put the hosts ahead.
Two goals in the last six minutes from Oscar Cardozo and Mehmet Ekici gave Trabzonspor a 3-2 victory versus second-bottom Karabukspor, while struggling Rizespor moved out of the bottom three by beating Eskisehirspor 3-0.
Bursaspor pulled off the fightback despite having Harun Tekin sent off for conceding the penalty for Mersin's 17th-minute opener.
Elsewhere, Orhan Sam's red card did not prevent Kasimpasa from overcoming Gaziantepspor 2-0 and Genclerbirligi drew 0-0 with Sivasspor.
