diff --git a/python/mozperftest/mozperftest/runner.py b/python/mozperftest/mozperftest/runner.py
index 761f32633e11e7a6a64a690a4ff07a48ed2f6864..7a9d28f74bb175feae9547a77addce0faaf875f3 100644
--- a/python/mozperftest/mozperftest/runner.py
+++ b/python/mozperftest/mozperftest/runner.py
@@ -208,6 +208,8 @@ def run_tools(mach_cmd, kwargs):
         artifacts = _create_artifacts_dir(kwargs, SRC_ROOT)
     tempdir = tempfile.mkdtemp()
 
+    if kwargs.get("output"):
+        kwargs.pop("output")
     s = SideBySide(str(tempdir))
     s.run(**kwargs)