diff --git a/src/regex/match.c b/src/regex/match.c
index f6c3913..ffa3e62 100644
--- a/src/regex/match.c
+++ b/src/regex/match.c
@@ -336,7 +336,9 @@ static int _RegexMatcher_Create(RegexMatcher* matcher, Regex* regex, StringView
 		return stack_code;
 	}
 
-	RegexMatchThread* root_thread = _RegexMatchThreadGroup_NewThread(&matcher->top_group);
+	RegexMatchThread* root_thread = _RegexMatchThreadGroup_NewThread(
+		&matcher->top_group
+	);
 	if (root_thread == NULL) {
 		RegexMatchThreadGroup_Destroy2(&matcher->top_group);
 		DynamicArray_Destroy(&matcher->visitor_stack);
@@ -347,6 +349,7 @@ static int _RegexMatcher_Create(RegexMatcher* matcher, Regex* regex, StringView
 		DynamicArray_Destroy(&matcher->visitor_stack);
 		return ENOMEM;
 	}
+	root_thread->number = 0;
 
 	matcher->depth = 1;