Major S2

As I was watching Major S2, Goro's arrogance[confidence(?)] reminded me a lot of Tatsumi. I kept comparing the two characters. They both also have the determination to fight from the bottom and become the best. They are also both enjoy sports anime.  

The Kaido arc in Major is basically all of Diamond no Ace. Both are baseball animes with an overenthusiastic, wild pitcher as the main character. 

"Kaidou Arc" in Major reminded me a lot of "Pro-Hunter Exam Arc" in HxH. Two main characters have to team up with other applicants and to pass the qualifying examination they have to trust other members even if they are complete strangers. Both shows have other similarities, but I won't spoil it. Things often get nail bitingly intense each episode, prepare yourselves for unexpected turn of events. If you enjoyed one of them, you can get the same feeling from the other one. 

eternal rivalry, friendship and both are totally addicting 

Both sports animes about an immensely gifted son and all the effort, work and sacrifice it takes to live up to his own potential. (I put the recommendation on S2 of Major because of the age similarity, but you should start at S1 if you're going to!) 

Both are sports anime with a prodigy as a main character. Both protagonists, Goro and Ryoma, are in middle school. 

Baseball anime, both main characters are elite in baseball and take teams from nothing to victory...