diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index 15cfd7a2d71..97487fd0b22 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -112,7 +112,7 @@ class ClientRequestCreator<ByteBuffer> {
  public:
   ClientRequestCreator(ByteBuffer* req, const PayloadConfig& payload_config) {
     if (payload_config.has_bytebuf_params()) {
-      std::unique_ptr<char> buf(
+      std::unique_ptr<char[]> buf(
           new char[payload_config.bytebuf_params().req_size()]);
       gpr_slice s = gpr_slice_from_copied_buffer(
           buf.get(), payload_config.bytebuf_params().req_size());