Ba worked with Mourinho while at Chelsea between 2013 and 2014. The Senegal international left Samford Bridge for Besiktas in July 2014.
“I thought Chelsea would continue with Mourinho,” Ba told RMC.
“It’s rare to see Mourinho manage three years at the same team. And this has confirmed that.
“His methods are exhausting, very tiring. He’s someone who likes to win and when he loses, you could say that the sky comes crashing down on his head. Things get complicated when he loses because he gets annoyed. It looks like his face is overcome with anger, although this is probably not the case in reality.
“It’s because he is a winner – when he loses, it affects him. This is not bad – he’s proven, he has won an enormous amount of titles. Whether you like him or not, he does not leave you indifferent – though I’m speaking of him as a coach, not a man.”
The Mirror had linked West Brom and West Ham as being closely linked with the 30-year-old striker over the summer but he joined Chinese side Shenhua on a €14 million move instead.
Ba scored 29 goals in all competitions for the Black Eagles last season – a career high – and also provided nine assists.
The Senegal international was part of the side that reached the Europa League Round of 32 and finished the league in third place.
Besiktas travel to Ankara to take on Osmanlispor in the Turkish Super Lig this weekend. The Istanbul based club sit in first place with 35 points in 15 games.