Wesley Sneijder set the ball rolling in the 12th minute on Sunday when he ghosted into the penalty area to tap home from close range following good work by Felipe Melo.
The Dutchman doubled his tally eight minutes later firing home a left-footed thunderbolt from 20 yards, before Emmanuel Eboue rounded goalkeeper Sebastien Frey to make it 3-0.
And Sneijder completed his hat-trick two minutes before the break, capitalising on a defensive mix-up to send the ball into the roof of the net.
Didier Drogba's deft flick put Roberto Mancini's side five up in the 66th minute, before Selcuk Inan completed the rout with a curling effort two minutes from time to make it 6-0.
Sunday's victory saw Gala take full advantage of Fenerbahce's 2-1 defeat at Eskisehirspor on Saturday.
Dirk Kuyt pulled the visitors level after Henri Bienvenu had put Eskisehirspor ahead, but Erkan Zengin had the final word, sealing the three points in the 83rd minute.
Besiktas kept pace with the top two as they leapfrogged Sivasspor, who lost 3-0 at Konyaspor, with a 3-2 victory over Kayseri Erciyespor.
Kayserispor's goalless draw at home to Kasimpasa saw them climb off the foot of the table.
Elsewhere, Karabukspor picked up a 3-1 win against strugglers Elazigspor, Arkhisar Beldiyespor triumphed over Genclerbirligi by the same scoreline, Gaziantepspor won 1-0 at Antalyaspor, and 10-man Trabzonspor were held to a goalless draw at Rizespor.
‘Milan didn’t collapse against Liverpool in Istanbul. We lost focus for six minutes – for the other 114, we played an extraordinary, beautiful game’: AC legend claims they were 'extraordinary' against Reds in 2005 Champions League final
‘Charlton could have qualified for Europe, but selling Scott Parker to Chelsea made the difference. The manager didn’t want him to go and there was a disagreement’: Former Addicks star highlights key reason why they failed to maintain 2003/04 form
