Casper is irritated with Ulysses after their conversation earlier because there are just certain jokes he isn't prepared to laugh at yet and his unfortunate friend happened to stumble his way into one, pushing him just far enough and just hard enough to earn a spark of genuine anger that's kept him scowling and silent and evasive ever since the group got together to head for the match. The fact that he ended sitting beside the other boy is just bad luck. Still, as the match starts, he focuses on the game and mostly ignores Ulysses as he counts the points and silently runs the same equations in his head.

Suddenly seeing the Seekers turn into a dive makes him stiffen in his seat and he barely notices when Ulysses seizes his hand and holds it hard. He returns the pressure without thinking, his own grip like that of a vice. Then Reid catches the snitch and the game is miraculously over. And they've got a chance again. A chance to win this thing and give Leo the sendoff he deserves. He's up on his feet with the others and, while he's not cheering, he is smiling broadly as he mutters, disbelieving, "Holy shit!" He peers out over the field to make certain this isn't some kind of mistake and utters a startled noise when Ulysses pulls him into a hug, but doesn't shove the other boy off him (another miracle?) and actually hugs him back instead.

He will almost certainly deny this last part later. But for now, he's just as excited as his teammates.