Lower one's flag.

　　Play second fiddle.

　　Take a back seat.

　　To sit at a person's feet.

　　eg：He is willing to eat humble pie under that scholar after reading his book.

　　中英俚语俗语来源：左传·值十五年：“皇天后土，实闻君之言，群臣敢在下风。”

　　反义词：不甘人后 Not to be outdone.