Nikolos Bassilashvili mainly plays on the ATP World Tour. As a top 50 player, he usually has a place in the main field without having to play in qualification. At the Challenger level, he has won four individual titles so far. He also won eight singles and two doubles titles on the Future Tour. On the World Tour , he qualified for a main field for the first time in Bucharest in 2014 and met Ričardas Berankis in the first round , to whom he lost in three sets.
In 2016 he reached his first final on the World Tour in Kitzbühel , where he lost to Paolo Lorenzi in two sets. Bassilashvili is the first tennis player from Georgia who ever reached a final on the World Tour.
In 2018 in Hamburg he won the final in 3 sets against Leonardo Mayer , after having played his way into the main draw via qualification.