diff --git a/qutebrowser/browser/webengine/webenginetab.py b/qutebrowser/browser/webengine/webenginetab.py
index c9dd20717..93e1275d9 100644
--- a/qutebrowser/browser/webengine/webenginetab.py
+++ b/qutebrowser/browser/webengine/webenginetab.py
@@ -235,11 +235,11 @@ class WebEngineScroller(browsertab.AbstractScroller):
         self._tab.run_js_async(js_code)
 
     def to_point(self, point):
-        self._tab.run_js_async("window.scroll({x}, {y});".format(
-            x=point.x(), y=point.y()))
+        js_code = javascript.assemble('window', 'scroll', point.x(), point.y())
+        self._tab.run_js_async(js_code)
 
     def delta(self, x=0, y=0):
-        self._tab.run_js_async("window.scrollBy({x}, {y});".format(x=x, y=y))
+        self._tab.run_js_async(javascript.assemble('window', 'scrollBy', x, y))
 
     def delta_page(self, x=0, y=0):
         js_code = javascript.assemble('scroll', 'delta_page', x, y)
diff --git a/qutebrowser/utils/javascript.py b/qutebrowser/utils/javascript.py
index 9f7372758..4eaf63cd0 100644
--- a/qutebrowser/utils/javascript.py
+++ b/qutebrowser/utils/javascript.py
@@ -62,6 +62,9 @@ def _convert_js_arg(arg):
 def assemble(module, function, *args):
     """Assemble a javascript file and a function call."""
     js_args = ', '.join(_convert_js_arg(arg) for arg in args)
-    code = '"use strict";\nwindow._qutebrowser.{}.{}({});'.format(
-        module, function, js_args)
+    if module == 'window':
+        parts = ['window', function]
+    else:
+        parts = ['window', '_qutebrowser', module, function]
+    code = '"use strict";\n{}({});'.format('.'.join(parts), js_args)
     return code
diff --git a/tests/unit/utils/test_javascript.py b/tests/unit/utils/test_javascript.py
index 50fd4e91e..f7ff7da53 100644
--- a/tests/unit/utils/test_javascript.py
+++ b/tests/unit/utils/test_javascript.py
@@ -138,6 +138,10 @@ def test_convert_js_arg(arg, expected):
         assert javascript._convert_js_arg(arg) == expected
 
 
-def test_assemble():
-    expected = '"use strict";\nwindow._qutebrowser.foo.func(23);'
-    assert javascript.assemble('foo', 'func', 23) == expected
+@pytest.mark.parametrize('base, expected_base', [
+    ('window', 'window'),
+    ('foo', 'window._qutebrowser.foo'),
+])
+def test_assemble(base, expected_base):
+    expected = '"use strict";\n{}.func(23);'.format(expected_base)
+    assert javascript.assemble(base, 'func', 23) == expected