The Blues launched an investigation into claims Sturridge was called a "monkey" as he came on as a substitute in last month's 1-1 draw in Belgium following a complaint from another supporter.
The fan accused of racism - who was sitting in the same section as the likes of British Airways chairman Martin Broughton and computer multi-millionaire Peter Harrison in the Cristal Arena's exclusive 100-euro seats - was alleged to have shouted: "They are bringing on the monkeys." However, none of the 16 supporters Chelsea interviewed during their investigation was able to corroborate the accusation.
A club spokesman said in a statement: "Following the UEFA match in Genk, Belgium, the club received a report from an executive club member that another supporter had used racially-discriminatory language during the match.
"This was said to have been directed at Daniel Sturridge, who came on as a substitute in the second half. As with all such reports, the club takes such issues very seriously and has conducted a thorough and detailed investigation.
"This has involved interviewing 16 supporters who, according to the seating plan, were sat in the area of the stadium concerned. A formal statement was also taken from the complainant.
"In spite of the very lengthy enquiries, the evidence did not identify conclusively any individual as being responsible for making the comments. No other witnesses reported having heard the alleged comments or anything similar.
"In the absence of clear evidence, it is not possible to reach any conclusion on which to pursue the complaint further. For these reasons, the club is unable to take any further action.
"We should stress that the club welcomes the diligence of all supporters to report any behaviour which is offensive and unacceptable and will always treat any such complaint seriously."
The accused fan was also alleged to have joined in the abuse of QPR defender Anton Ferdinand during the Genk game, something which began in the away section. The club are still trying to identify those heard to chant "Anton Ferdinand, you know what you are" in apparent support for Chelsea captain John Terry, who is waiting to learn whether he faces criminal charges over claims he used a racial slur against Ferdinand. Terry categorically denies the allegation.
Source: PA
Source: PA