Who is "Miyuki-senpai"?
Miyuki-senpai is from Daiya no Ace. The anime is centered around Sawamura (MC) and Miyuki's relationships as pitcher-catcher (the author said so). Sawamura wants Miyuki to acknowledge him as a capable pitcher, yet his rival on the same team, Furuya, as the ace, made Miyuki pay attention to him more. Sawamura struggled to make the best battery with Miyuki, hence 'notice me senpai'.