What does the cryptic crossword clue "Ritual performed with zest in battle (10)" mean?

The definition is "battle". The wordplay uses an anagram. anagram of RITUAL + ZEST = AUSTERLITZ; definition: "battle" The answer is AUSTERLITZ.

Ritual performed with zest in battle (10)

Guardian Cryptic #29367 | 3 Down | 2024-04-26 flower