diff --git a/core/src/main/java/org/springframework/security/authorization/AuthorityAuthorizationManager.java b/core/src/main/java/org/springframework/security/authorization/AuthorityAuthorizationManager.java
index c3dbb4b40f..43af8a5cb8 100644
--- a/core/src/main/java/org/springframework/security/authorization/AuthorityAuthorizationManager.java
+++ b/core/src/main/java/org/springframework/security/authorization/AuthorityAuthorizationManager.java
@@ -16,7 +16,6 @@
 
 package org.springframework.security.authorization;
 
-import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.function.Supplier;
@@ -133,7 +132,7 @@ public final class AuthorityAuthorizationManager<T> implements AuthorizationMana
 	}
 
 	private boolean isAuthorized(Authentication authentication) {
-		Set<String> authorities = getAuthoritySet();
+		Set<String> authorities = AuthorityUtils.authorityListToSet(this.authorities);
 		for (GrantedAuthority grantedAuthority : authentication.getAuthorities()) {
 			if (authorities.contains(grantedAuthority.getAuthority())) {
 				return true;
@@ -142,14 +141,6 @@ public final class AuthorityAuthorizationManager<T> implements AuthorizationMana
 		return false;
 	}
 
-	private Set<String> getAuthoritySet() {
-		Set<String> result = new HashSet<>();
-		for (GrantedAuthority grantedAuthority : this.authorities) {
-			result.add(grantedAuthority.getAuthority());
-		}
-		return result;
-	}
-
 	@Override
 	public String toString() {
 		return "AuthorityAuthorizationManager[authorities=" + this.authorities + "]";