They lost the match in humiliating fashion, and team morale plummeted.
Tips
usage
Two layers: literal (dirty face) and figurative (beaten down, embarrassed). Context decides which. 灰头土脸地回来 could be either a miner after work or a candidate after a lost election.
memory
灰 (ash) + 头 (head) + 土 (dirt) + 脸 (face) = "ash-head, dirt-face." Picture someone who just crawled out of a dusty hole.
