How do you beat Clair on Pokemon HeartGold?

If you want to beat Clair, you should try and get an Ampharos and Gyrados. Ampharos can learn thunder punch and that will beat her Gyrados then follow it up with your own Gyrados that knows Ice fang which will crush her Dragonair. Her Kingdra is the storgest for it is on lv.41 so if your Ampharos is higher than that you can probably beat her.