diff --git a/test/util/socket_util.cc b/test/util/socket_util.cc
index 4d8ba6d50..650b422ae 100644
--- a/test/util/socket_util.cc
+++ b/test/util/socket_util.cc
@@ -1075,9 +1075,9 @@ void SetupTimeWaitClose(const TestAddress* listener,
     ASSERT_THAT(poll(&pfd, 1, kTimeout), SyscallSucceedsWithValue(1));
   }
 
-  // Close the passive socket. This ensures that it transitions from LAST_ACK to
-  // CLOSE.
-  passive_closefd.reset();
+  // This sleep is needed to reduce flake to ensure that the passive-close
+  // ensures the state transitions to CLOSE from LAST_ACK.
+  absl::SleepFor(absl::Seconds(1));
 }
 
 constexpr char kRangeFile[] = "/proc/sys/net/ipv4/ip_local_port_range";