The Israeli, 31, was booed by the home support and was substituted during the interval of their 1-0 victory on July 24.
The club were unsure at first whether the jeering was antisemitic but, after a further investigation, concluded it was.
A club spokesman said: "Notwithstanding most fans behaving appropriately on the night, we believe Yossi was subjected to antisemitic abuse by a number of supporters at the game.
"Such behaviour is offensive, totally unacceptable and has no place in football."
The Blues face Aston Villa in the final of the Asia Trophy on Saturday, July 30.