A request to perform an operation, such as a remote direct memory access (RDMA) write operation or a send operation that writes to memory, is sent from a sending input/output (I/O) adapter (e.g., an RDMA-capable adapter) to a receiving I/O adapter. The receiving I/O adapter receives the request and initiates performance of the operation, but delays sending an acknowledgment for the operation. The acknowledgment is delayed until the operation is complete (i.e., until the memory is updated and the data is visible to the remote processor), as determined by a read operation initiated and performed by the receiving I/O adapter transparent to the sending I/O adapter.