---mysql root login issue

 mysql -u root -p
Enter password:
ERROR 1698 (28000): Access denied for user 'root'@'localhost'

$ sudo mysql -u root # I had to use "sudo" since is new installation

mysql> USE mysql;
mysql> UPDATE user SET plugin='mysql_native_password' WHERE User='root';
mysql> FLUSH PRIVILEGES;
mysql> exit;

$ service mysql restart