Following their late, late show against Samsunspor the previous weekend, Fenerbahce had the chance to close the gap to Galatasaray on Friday and put a little pressure on them.
They visited the team slumped at the bottom of the table and almost certainly facing relegation, Karagumruk, barring an incredible late surge.
Perhaps surprisingly, Fenerbahce made a few changes ahead of the game, resting talisman Marco Asensio.
Karagumruk started the game sharply, and took the lead after 15 minutes when Bartug Elmaz - who is actually on loan from Fenerbache - scored against his parent club.
Fenerbahce were really struggling to get anything going while also being caught out by Karagumruk's counter-attack, as they continued to create clear-cut chances at will.
And the home side were rewarded for their performance on the stroke of half time, with Serginho doubling their lead.
Knowing they were in serious trouble, Fener brought on Asensio, Douglas Nene, Archie Brown and Anthony Musaba at half time, but they did little to change proceedings.
It was a baffling second-half display from Fenerbahce. Instead of showing desperation to stay in the title race, they were slow and lethargic, passing the ball from side to side with very little impetus - much to the satisfaction of Karagumruk.
Instead, Fenerbahce completely fizzled out, almost accepting their fate and falling to a 2-0 defeat, with their Super Lig title hopes now in complete tatters.
It was their first loss in the league this season, to go alongside their 16 wins and nine draws, while they have just one win in their last four Super Lig games.
Losing a game is one thing, but to do so against the worst team in the league in such an awful and given-up manner is pretty embarrassing.
An emergency board meeting was called by the club, and after mulling over the futures of coach Domenico Tedesco and sporting director Devin Ozek, both remained in their roles... for now.
There is turmoil behind the scenes at the moment as those in charge ponder what is next.
They need to start looking over their shoulder, too.
Trabzonspor continued their excellent season with a 1-0 win over Rizespor, as Paul Onuachu netted his 21st goal of the Super Lig season.
As a result, they went level on points with Fenerbahce, and the race for the second Champions League spot is now wide open.
It would be a remarkable achievement for Fatih Tekke and his men to finish second in the league, while for Fener it would be utterly humiliating, given all the money they spent in the summer.
Galatasaray march imperiously on
After Fenerbahce's defeat, motivation was high for Galatasaray players and fans, knowing they could go seven points clear at the top of the table.
They hosted an Istanbul Basaksehir side who had just one loss in their last 12 Super Lig games, and were making a real push at the European spots.
The first half was a real tussle, with Basaksehir giving it a real go against a Galatasaray team full of confidence after recent wins over Besiktas and Liverpool.
With the score 0-0 at half-time, Galatasaray came out from the break with extra energy, and the game swung further in their direction when Basaksehir had a man sent off for a second yellow.
From the resulting free kick, the brilliant Wilfried Singo volleyed home for his first goal for the club, and the floodgates opened.
Victor Osimhen then made it 2-0 with a deflected effort for his 19th of the season in all competitions, before 18-year-old Renato Nhaga came off the bench for his first league goal in Galatasaray colours since signing from Casa Pia in January, leading to jubilant celebrations among teammates for the teenager.
The score finished 3-0, and it felt like a big result in the title race.
While not mathematically done, it would be a major shock if Galatasaray - who are playing so well at the moment - were to throw it away from this point on.
A third clean sheet in a row also showcases how determined they have been at the back, as well as how good goalkeeper Ugurcan Cakir has been.
Only Galatasaray have won the Super Lig four times in a row before (1996-2000), and this current group stand on the verge of doing that.
Alongside their exploits in Europe, they remain on course for an excellent season, with manager Okan Buruk deserving a lot of credit.
They have an incredibly strong team and have spent money well over the last 12 months, and this is their reward.
Team of the Week
Mohamed Bayo is the Flashscore Player of the Week, according to our very own internal ratings system, after scoring twice and picking up an assist in Gaziantep's 4-1 win over Antalyaspor.
Four Galatasaray players - Singo, Eren Elmali, Yunus Akgun and Noa Lang all make the team, while Besiktas' Orkun Kokcu, Ersin Destanoglu, and Junior Olaitan are included following a 2-0 win over Genclerbirligi.