He played at the Nanjing Pearl Spring tournament in September -- October 2009 . This lifted him to an Elo rating of 2801 . His performance at the September -- October 2009 Nanjing Pearl Spring tournament has been described as one of the greatest in history and lifted him to an Elo rating of 2801 , making him the fifth player to achieve a rating over 2800 â `` and aged 18 years 10 months at the time , by far the youngest to do so .