“My manager told me Mourinho was interested,” Niasse told The Guardian.
“He said Mourinho liked the way I play and had been looking at me since I was in Turkey [with Akhisar Belediyespor].
“He was very interested in me for this last transfer window but then he was sacked.”
Under his stewardship of former Galatasaray manager Hamza Hamzaoglu the 25-year-old became one of the most sought after players in the Super League at Akhisar scoring 15 times and providing seven assists in 40 appearances.
Niasse was snapped up by Lokomotiv Moscow in the summer of 2014 for £4 million and scored 13 times in 23 games for the Russian side.
Galatasaray and Chelsea were both in the race to sign Niasse over the summer transfer window but Everton ended up beating both clubs to his signature.
Everton then went onto sign the Senegal international on a £13.5 million deal making him the third most expensive signing in the Toffees history.