The fight between Rakan and his partner Kagetario and Negi/Nagi and Kotario is a classic the Student vs. the Master fight. Rakan is the master while Negi the student. In some way, Rakan is only interest in himself when he decided to enter the fight. Yet as Negi's Master, Rakan is doing more for Negi by joining the tournament. Rakan has two motives, the money and to teach Negi a lesson or two. Oddly, Rakan is not being totally selfish. He wants to help Negi.
Rakan had noticed that one of Negi's strengths as a fighter is his intelligence. Negi has to used his brains to figure out how to defeat Rakan and his partner. Apparentily, Rakan wants Negi to start using his brains more as well as his other strengths.