Five-time world champion Magnus Carlsen risks losing his world number one chess ranking for the first time in 15 years after his live rating slipped to 2,807.2. Carlsen lost 15.8 rating points following five draws and a defeat to Armenia's Haik Martirosyan at Total Chess tournament. American Fabiano Caruana's live rating has reached 2,800, leaving him just 7.2 points behind.