diff --git a/qutebrowser/utils/completion.py b/qutebrowser/utils/completion.py
index da48586ae..ce68d81d6 100644
--- a/qutebrowser/utils/completion.py
+++ b/qutebrowser/utils/completion.py
@@ -280,7 +280,7 @@ class CompletionFilterModel(QSortFilterProxyModel):
 
     def __init__(self, parent=None):
         super().__init__(parent)
-        self.pattern = ''
+        self._pattern = ''
 
     @property
     def pattern(self):