Unknown factor (不確定要素 Fukakutei Youso) is the 177th chapter of manga, Baby Steps.
Characters in Order of AppearanceEdit
By not focusing on how to enter the zone at will, Eiichiro's tennis style is evolving again, making Nabae more wary on Eiichiro's "reckless" attacks.
Eiichiro creates a vision of his victory by considering of increasing the power of his shots and variety of his change-of-pace strategy. Nabae gets the first game for the final set but realizes that Eiichiro is doing unexpected again - similar on what he had done before in their match - thus, Nabae decides to finish the match as quickly as he can.
Eiichiro keeps on losing - either he is cornered by Nabae in Eiichiro's strategy or he used too much power on his attacks. He tries to use Iwasa's strategy - a lob volley - but it still fails. Nabae becomes wary of Eiichiro's "reckless" attacks because he notices that whenever Eiichiro is cornered, Eiichiro will definitely test new patterns in order to evolve his tennis style more.
After several "reckless" attacks, Eiichiro's condition in the game is improving. He did not realize that by changing his mindset, it actually takes him closer to the zone and his field of vision becomes wider.