Ryan Babel put the Lions ahead in the 11th minute, but Rachid Ghezzal converted the penalty to give Besiktas an equalizer in the 42nd minute. The home side responded quickly with Radamel Falcao's penalty goal before the first half ended.
In the second half, Arda Turan doubled the lead for his team, who secured a crucial derby win at the Turk Telekom Stadium.
Galatasaray, currently in third place with 78 points, reduced the gap to leaders Besiktas to three points with this crucial victory.
Fenerbahce are now in the second spot with 79 points.
