diff --git a/src/plugins/languageclient/languageclientcompletionassist.cpp b/src/plugins/languageclient/languageclientcompletionassist.cpp
index e9e8ad64533..e10729987ce 100644
--- a/src/plugins/languageclient/languageclientcompletionassist.cpp
+++ b/src/plugins/languageclient/languageclientcompletionassist.cpp
@@ -233,7 +233,7 @@ public:
     // GenericProposalModel interface
     bool containsDuplicates() const override { return false; }
     bool isSortable(const QString &/*prefix*/) const override;
-    void sort(const QString &/*prefix*/) override;
+    void sort(const QString &prefix) override;
     bool supportsPrefixExpansion() const override { return false; }
 
     QList<AssistProposalItemInterface *> items() const { return m_currentItems; }
@@ -247,19 +247,21 @@ bool LanguageClientCompletionModel::isSortable(const QString &) const
     });
 }
 
-void LanguageClientCompletionModel::sort(const QString &/*prefix*/)
+void LanguageClientCompletionModel::sort(const QString &prefix)
 {
     std::sort(m_currentItems.begin(), m_currentItems.end(),
-              [] (AssistProposalItemInterface *a, AssistProposalItemInterface *b){
+              [&prefix] (AssistProposalItemInterface *a, AssistProposalItemInterface *b){
         const auto lca = dynamic_cast<LanguageClientCompletionItem *>(a);
         const auto lcb = dynamic_cast<LanguageClientCompletionItem *>(b);
         if (!lca && !lcb)
             return a->text() < b->text();
         if (lca && lcb)
             return *lca < *lcb;
-        if (lca && !lcb)
-            return true;
-        return false;
+        if (prefix.isEmpty())
+            return lca && !lcb;
+        if (!lca)
+            return a->text().toLower().startsWith(prefix.toLower());
+        return !b->text().toLower().startsWith(prefix.toLower());
     });
 }