Days 36 & 37[edit]
On Day 36, talk to Kurita and on Day 37, talk to Mamori. On each day, they will each give you a mini-game (with Mamori's being a bit more challenging). Finish the mini-game and the day will end.
Day 38[edit]
It will be clear by now that your next opponents will be the Taiyō Sphinx. After hearing the news, go to the Devil Bats HQ. The Ha-Ha Brothers aren't very happy, and decide to quit the Devil Bats. Unfortunately, that doesn't seem to be where the trouble ends for the Ha-Ha Brothers. Thinking they can easily take him on, they pick a fight with Mamoru Banba of the Sphinx. They don't seem to be aware of the fact that Mamoru Banba is the star player of the Sphinx, playing center for the team. Though this probably isn't the case - they just have over-confident attitudes. The fight doesn't work out in favor of the Ha-Ha Brothers, and Banba beats them. Feeling shameful, they rejoin the Devil Bats and train harder with the goal of defeating Banba and the Sphinx at the upcoming game.
Day 39[edit]
Go to the Devil Bats HQ. Unlike other days, you won't be able to enter this time - there will be a large truck in the way. The Ha-Ha Brothers come along to show off their newly-obtained determination and help out with the unblocking of the HQ. Give the Ha-Ha Brothers a hand by sliding 
across the screen as quickly as you can. After the mini-game, the truck will be moved and you'll be free to enter the HQ. The day will then come to a close.
Day 40[edit]
Nothing especially significant happens today. Talk to Yukimitsu at the entrance of the school and then go to the Devil Bats HQ. Sena and the Ha-Ha Brothers will redo their bench presses from when they first joined the team. All four of them have greatly improved as evidenced by comparison of weights lifted. Tomorrow will be your game with the Sphinx! Save your game (just in case) before the day can end.