Chelsea have lodged an official complaint over abuse received by Yossi Benayoun in their match last week against a Malaysian XI.
Having reviewed the match, in which Benayoun's every touch was jeered, the club believe abuse directed at the Israel international was anti-Semitic in nature and, therefore, have complained to the Malaysian FA.
A statement read: "Notwithstanding most fans behaving appropriately on the night, we believe Yossi was subjected to anti-Semitic abuse by a number of supporters at the game."
The statement continued: "Such behaviour is offensive, totally unacceptable and has no place in football.
"The club did not make representations at the time as it was initially unclear as to the nature of the abuse Yossi received, as several players from both teams experienced similar treatment, sometimes louder and longer.
"However, having taken time to consider the issue fully, it has become apparent that a formal complaint was necessary.
"Our stay in Malaysia was, on the whole, a very positive experience for all the team travelling on the pre-season tour.
"It is a shame, therefore, that the behaviour of a minority of supporters is also a memory we take away."
Malaysia as a country is a strong supporter of Palestine and does not recognise Israel.