diff --git a/biscuit/apps/chronos/views.py b/biscuit/apps/chronos/views.py
index e7c3eabfbdde59949b406d4603e543517870361c..b318a82e72b3d38a414a52573c786b6ba7a52c91 100644
--- a/biscuit/apps/chronos/views.py
+++ b/biscuit/apps/chronos/views.py
@@ -153,7 +153,7 @@ def edit_substitution(request: HttpRequest, id_: int, week: int) -> HttpResponse
             edit_substitution_form.save(commit=True)
 
             messages.success(request, _('The substitution has been saved.'))
-            return redirect('lessons_day_by_date', when=week_days(week)[lesson_period.period.weekday].strftime('%Y-%m-%d'))
+            return redirect('lessons_day_by_date', when=week_days(week)[lesson_period.period.weekday - 1].strftime('%Y-%m-%d'))
 
     context['edit_substitution_form'] = edit_substitution_form