Seeing that Lu Wuhu didn't help Ye Mo say anything, Yan Guan breathed easy. He was scared that Lu Wuhu would be domineering and forcefully take away Luo Susu. In order to preserve their face, they could only fight with Lu Wuhu. Even if they won, the result wouldn't be what Yan Guan wanted.
They would also be offending Pill City in the process.
After elder Fan brought up the tournament, Ye Mo didn't let Lu Wuhu forcefully attack and Lu Wuhu didn't stand up himself. This made Yan Guan breathe easy and guess the relationship between the two. If their relationship was really as Ye Mo said, then Lu Wuhu should've said something