diff --git a/bundles/grafana/dashboard-rows/wireguard.py b/bundles/grafana/dashboard-rows/wireguard.py
index 1d5bd6d..bd71277 100644
--- a/bundles/grafana/dashboard-rows/wireguard.py
+++ b/bundles/grafana/dashboard-rows/wireguard.py
@@ -67,7 +67,7 @@ def dashboard_row_wireguard(panel_id, node):
             _value: r._value / 1000000000
         }})
     )
-    |> derivative(unit: 1s)
+    |> derivative(unit: 1s, nonNegative: true)
     |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
     |> yield(name: "last_handshake_time_ns")""",
                     'resultFormat': 'time_series',