Fifty years or a hundred years from now, people may not exactly realize the iconic nature of "Gunsmoke", so there will be "landmark" episodes that might keep the iconic status of this Western TV series.
This is the masterpiece episode, perhaps because it is the guest stars that are the entire story.
There are five guests who overshadow Matt Dillon and the others in drama, which is how a really good TV series works. The "regular" players are symbolic of the society, culture, and mores.
An aging billiards master finds himself in partnership with a young upwardly mobile man and the man's lady. The young upwardly mobile man is a sort of agent, and the pool master beats a cattle baron at pool for some good money, so the cattle baron brings in the new young buck pool player, who comes in very cocky.
The theatrics here are superb with a great switch ending involving the characters, notably the two younger men.