diff --git a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
index b6af32a32a..75e89dcbb8 100644
--- a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
+++ b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
@@ -317,7 +317,7 @@ insertStatement =
   )
   break
   [
-    'ON DUPLICATE KEY UPDATE' 'SET' setClauses [ 'WHERE' condition ]
+    'ON DUPLICATE KEY UPDATE' [ 'SET' ] setClauses [ 'WHERE' condition ]
   | 'ON DUPLICATE KEY IGNORE'
   | 'ON CONFLICT' ( 'ON CONSTRAINT' constraintName | '(' fieldNames ')' ) 'DO'
     (
diff --git a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
index 26494752f9..25e99e87fe 100644
--- a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
@@ -1699,7 +1699,9 @@ final class ParserImpl implements Parser {
             throw ctx.expected("DEFAULT VALUES", "SELECT", "SET", "VALUES");
 
         if (parseKeywordIf(ctx, "ON")) {
-            if (parseKeywordIf(ctx, "DUPLICATE KEY UPDATE SET")) {
+            if (parseKeywordIf(ctx, "DUPLICATE KEY UPDATE")) {
+                parseKeywordIf(ctx, "SET");
+
                 InsertOnConflictWhereStep<?> where = onDuplicate.onDuplicateKeyUpdate().set(parseSetClauseList(ctx));
 
                 if (parseKeywordIf(ctx, "WHERE"))