What does the cryptic crossword clue "Emperor overwhelmed by part of Soviets' army (4)" mean?

The definition is "army". The wordplay uses a hidden word. Hidden in "emperor overwhelmed by part of sovieTS' ARmy" The answer is TSAR.

Emperor overwhelmed by part of Soviets' army (4)

Independent Cryptic #11843 | 21 Across | 2024-09-24 flower