This whole "attach character / emotional development to some sort of shounen plot device" is really taking the wind out of the sails of the first big peak of their relationship.
Earlier the manga's development was slow, but it was fitting with Senpai-kun's timid personality slowly coming out of his shell. It could've been focused more on that, but what they did wasn't unreasonable.
But this, idk, just seems stupid. What if he doesn't get first? What if she loses? Does misfortune even exist in these saccharine, slice of life, romance comedies? Even if they hit us with the "oh they woke the fuck up and realized they should be true to themselves and be honest about their feelings without having to add weird conditions", we'll still have wasted all this time on what basically feels like filler.
A better manga would've focused more on their emotional state (e.g., like how Senpai helped Nagatoro get back into judo for real) so that they could do more emotional growth here, instead of just plot for plot's sake. Blue Box and Dangers in my Heart both do a much better job of this (not without their own issues, of course).