How do i get my cat to accept a bath when he needs one?

He's a rescued cat we rescued him last November. Today he needed a bath. So i brushed him out, he loves to be brushed. He has a dandruff problem so i use a medicated shampoo for cats. But when i try to bathe him, its very hard because he tries to climb out, a/or cling onto the sides of the bathtub. He never bites or scratches, hes just afraid of the water. I know cats hate water, but he really needed a bath. I've tried tips from sites on how to bathe cats, like giving him treats afterwards and that didn't work. Hes not mean or anything hes actually very sweet, and really this is the only time i ever have a problem with him. But any help is appreciated! Thanks!