Where did Guan Gong's war against Qin Qiong come from? What is it used to describe? What do you mean?

After the master's cross talk "vs" is about a rich man in Shandong who invited a troupe to perform for his father's birthday. The old man was uneducated and a bandit, so he forced the troupe to play Guan Gong against Qin Qiong (because Guan Gong was from Shaanxi and Qin Qiong was from Shandong, I wanted to see who was better, but I didn't know that Guan Gong was from the Three Kingdoms period and Qin Qiong was from the Sui and Tang Dynasties). This is probably the plot, which is often used to describe irrelevant things.