Reilly Opelka's latest 'rating' revealed: the views from his hotel room in Madrid

Reilly Opelka has thoughts (again).

The outspoken American has dished more than a few jabs since returning to the tour in earnest from injury this year, and this week, he set his sights (literally) on the player accomodations at his first Mutua Madrid Open in three years.

Rather than showing off famous Madrid sights including Plaza Mayor and the Royal Palace of Madrid on social media, Opelka's Instagram showcased an alleyway view from his window, with the night sky impeded by another building immediately adjacent to his hotel.

"Madrid sunset views are the best," he quipped sarcastically on his Instagram story ahead of the start of the ATP Masters 1000 event.

Read more: Must-do sights and bites in Madrid from The Tennis Traveler

Other targets of Opelka's rating system this year have included chair umpire Greg Allensworth and doubles players writ large. For example, he called the former the "worst ump on tour" after he awarded Opelka a controversial point penalty during a match against Cameron Norrie in Dallas.

“He's real bad, Opelka said of Allensworth. "Almost changed the outcome of that match just because he doesn't really know what he's doing."

Read more: Reilly Opelka sounds off on Greg Allensworth, lack of accountability

He also criticized the latter in the aftermath of the announcement of the US Open's revamped mixed doubles event, saying that there's "no such thing" as a doubles specialist, and that the discipline is for "failed singles players."

"They don’t sell a single ticket,” he wrote on social media. “They take up practice courts/physios/resources. They don’t turn a profit and they complain that they don’t make enough [money]. That’s pretty greedy behavior if you ask me.”

While there has yet to be any (public) direct interactions between Opelka and the targets of his previous criticisms, the 6-foot-11 big man will have at least one more night in his close quarters: He'll faces Australian lucky loser Rinky Hijikata in the first round on Thursday.