Mr Curtis took exception, and pointed out that his humiliation occurred in the semi-final of Mastermind. He sailed through the first round, answering specialist subject questions on the rock band The Jam.
Moreover, he had won £250,000 on ITV1's Who Wants To Be A Millionaire? 18 months previously, of which the Channel 4 programme had failed to make any mention.
Mr Curtis told Ofcom he had been "unfairly portrayed as being of low intelligence" and had not given his consent for the clip to be re-broadcast.
However, Ofcom dismissed the complaint. The watchdog ruled that the programme "was clearly intended to be a light-hearted and humorous look at past television events" and said that Walliams's commentary was "not intended in any way to be a serious examination of Mr Curtis's character, intelligence or competence".
It stood by the comments because "this was the worst performance ever seen on Mastermind in relation to a chosen specialist subject".
Mr Curtis, a probation service administrator and founder of a pub quiz league in his home town of Castleford, West Yorks, managed a final score of eight after gaining seven points in the general knowledge round. He said he "plucked the subject [Carrey] out of thin air" because he had not expected to reach the semi-final.