Last season's runners-up came from behind to record a 2-1 victory at Rizespor on Saturday and now hold an eight-point lead at the summit.
Cameroonian attacker Leonard Kweuke gave Rizespor a surprise lead after 11 minutes.
However, Cristian Baroni levelled for Fenerbahce on the stroke of half-time and Pierre Webo then popped up with the winning goal in the 83rd minute.
Fenerbahce have now won 11 games out of 14, but Galatasaray - 2-0 winners over Elazigspor on Friday - were the only other member of the top five to claim three points.
Gala's triumph was a routine one set up by goals inside the first seven minutes from Selcuk Inan and Burak Yilmaz.
Elazigspor were unable to respond and remain three points adrift at the foot of the table having now lost 10 league games in succession.
Second-placed Kasimpasa were held to a 1-1 draw at Antalyspor on Saturday in an ill-tempered game featuring three red cards.
Sanharib Malki gave Kasimpasa the lead in the 55th minute, only for Gokcek Vederson to swiftly respond.
The visitors then had Ilhan Eker and Ryan Babel sent off, the latter for dissent, in the 75th minute, but Antalyspor were unable to take advantage and were reduced to 10 men when Isaac Promise was dismissed late on.
Besiktas also had to settle for a 1-1 draw against Sivasspor on Monday, while Trabzonspor slipped to seventh courtesy of a 3-2 defeat at Gaziantepspor.
Hugo Almeida's fifth-minute strike - the Portuguese's ninth in the league this season - looked set to give Besiktas all three points, only for fellow countryman Manuel da Costa to level with 19 minutes remaining.
Cenk Tosun scored twice as Gaziantepspor made it three wins in a row.
Monday's other game saw Eskisehirspor climb into fifth with a 2-0 victory at Kayseri Erciyesspor.
Elsewhere, Akhisar Belediye beat Konyaspor 2-1, Joseph Akpala's goal gave Karabukspor a 1-0 win against nine-man Kayserispor and Bursaspor played out a 0-0 draw with Genclerbirligi.
