Fenerbahçe won against Al-Ittihad with some good football. Al-Ittihad are the defending champions of the Saudi Arabian Pro League. Their friendly matches won't mean much, of course, but you can't ignore the fact that they have a star studded squad. Al-Ittihad may not have pushed too hard in this match, but the fact that Fenerbahce are playing with this tempo in the preseason is a promising development for the long term.
If reinforcements like Skriniar and Asensio are made soon, it won't be too difficult for Fenerbahce to beat Feyenoord in the UCL qualifiers. But it's important to underline that it's wrong to read the whole season on the basis of one friendly. We don't know if Mourinho will continue this system. Fenerbahçe can start well and finish badly again.