For this trophy you'll need to earn 4 S Ranks across any Boss Battles.
For FACTORS on reaching high Rank for Boss/Pseudo battles please consult with this trophy solution:
The EARLIEST* you can earn this achievement is in Chapter 4: The Birth of Naruto. The battles needed to S Rank for this achievement are as follows:
-Nine Tails' Attack: Third Hokage vs Nine-Tails, Minato vs -Masked Man.
-The Agitated Five Kage Summit: Sasuke vs Gaara, Sasuke vs Samurai, Sasuke vs Mizukage
-Hero and Avenger- Naruto vs Sasuke
-Overcoming Hatred: Naruto vs Nine-Tails* earliest
-Threat of the Seven Swordsman: Guy, Sakura, Lee, vs 6 Swordsman, Kakashi vs Zabuza
-The Rumbling Coast: Choji vs Gedo Statue
-Bet the Future: 5 Kages vs Madara Uchiha
-The Last Battle: Naruto vs Jinchuriki & Tobi
If, for any reason, you aren't able to earn an S Rank no worry. You can retry ANY battles post-story in the Ninja World timeline for another try.