BBC One's celebrity dancing show received on average 800,000 more viewers than the ITV singing competition.
At it's peak on Sunday evening, Strictly saw 9.4 million tune in, while X Factor had a slump with 8.3 million.
Simon may not have been happy with being beaten, but he took to Twitter to admit defeat.
He wrote: "So the numbers are in. Strictly peak 9.4. X Factor peak 9.2. Round one to them. Such a shame they were both on at the same time."
Speaking at the X Factor launch earlier this month, Simon insisted that Strictly's tactics in airing at the same time were 'aggressive' and 'competitive'.
He said: "I don't pay too much attention. I mean, they are incredibly competitive with us.
READ: CHERYL FERNANDEZ-VERSINI BLASTS STRICTLY, SAYS X FACTOR 'GIVES CHANCE OF A LIFETIME'
"They say they're not but they are and we just found out that they put the show head-to-head with us which is quite aggressive and they did this in the past and I always say it annoys me because I think it's not what the viewers want."
Simon added that it's the viewers who end up losing out in the long-run, and said: "I don't worry about the ratings. What we do it try and make a better show than them and I think you need that kind of incentive so you don't complacent about everything."