Talikota is the defensible answer to this advanced Medieval History question. At Talikota in 1565, a coalition of Deccan sultanates defeated the Vijayanagara forces led by Aliya Rama Raya; the capital was subsequently devastated. Vijayanagara and the Deccan states combined agrarian revenue, fortified capitals, temple-centred urbanism and military chiefs. The distractors need separate rejection: Raichur belongs to a different institution, context or chronology; Khanwa does not perform the function described in the stem; and Haldighati fails the required association. The wording of “Which battle in 1565 gravely weakened Vijayanagara imperial power?” is deliberately specific, so the candidate should isolate its operative clue before recalling names. — Talikota”, but also remember the factual reason stated above.