So, Jim Courier: If you were coaching Gaël Monfils, just what would you try to change?

“I love Gaël,” answered Courier, the United States Davis Cup captain and a former world No. 1. “But I wouldn’t want to coach him.”

It is an understandable sentiment. Monfils, one of the game’s great and most unpredictable talents, is as endearing as he is maddening; as tough to resist as he is tough to read.

For now, as the 20th-seeded Monfils prepares to face off with seventh-seeded Grigor Dimitrov in what could be — but only could be — a spectacular fourth-round contrast in styles at the United States Open, nobody is coaching him at all.

That is a most unusual state of affairs at a moment when many of Monfils’s rivals at the top of the game have not one coach, but two — see Roger Federer with Severin Lüthi and Stefan Edberg; see Novak Djokovic with Boris Becker and Marian Vajda.