In response to receipt of a store-conditional (STCX) request of a processor core, the STCX request is buffered in an entry of a store queue for eventual service by a read-claim (RC) machine by reference to a cache array, and the STCX request is concurrently transmitted via a bypass path bypassing the store queue. In response to dispatch logic dispatching the STCX request transmitted via the bypass path to the RC machine for service by reference to the cache array, the entry of the STCX request in the store queue is updated to prohibit selection of the STCX request in the store queue for service. In response to the STCX request transmitted via the bypass path not being dispatched by the dispatch logic, the STCX is thereafter transmitted from the store queue to the dispatch logic and dispatched to the RC machine for service by reference to the cache array.