3rd Gen Defeating LeafGreen Champion with Charizard Only

Hello fellow Poke players! I am in a bit of a pickle and I desperately need your help, so here are the details:

I have the game LeafGreen, but for my starter Pokemon I chose Charizard. Now, challenging the Poke Champ in the game, I only have Charizard (lv57) left in my team. His moves are: Blast Burn (pp 5/5), Sunny Day (pp 5/5), Dragon Claw (pp 15/15), and Fire Blast (pp 5/5) The Champ has Pidgeot (lv59), Blastoise (lv 75), Rhydon (lv?), Arcanine (lv73), Alakazam (lv 73), and Exeggutor(lv73). ------ Pidgeot is no problem, and because I discovered Sunny Day in my TM's Blastoise is no longer a problem. Who's a problem is Rhydon, who uses Rock Tomb and kills my Charizard in an instant. ----- If you know how to do the impossible, your help is greatly appreciated. If you can think of TM's that might help I could look for them in my TM box. I have 8 Full Heals. If you need any more details to help me I will gladly try and get them for you ---- A TRUE Poke player can solve this complex problem! Thank you!

Hmm, well never faced Champion with Pidgeot LV 59 with Blastoise LV 75. You are mixing up the post champion's team with current one.Morever, what's your other pokemon team.Don't tell me you used on Charizard only to pass elite four ?

Anyway, if I believe you in case, to beat Rhydon you need to come at least with X special attack and hit with dragon claw.