Slade wins. Both are master martial-artist probably one of the best in DCverse. But Slade's discipline/technique's intention is to kill his target where as Bruce's is to neutralize or immobilize. Slade knows more killing moves than Bruce does. Slade has more of a superhuman physical qualities. Bruce is only above-normal or peak-human. This hand-to-hand fight goes to Slade.
Well, no. Slade has said before that he is an inferior fighter in terms of skill to Batman, and beats him through his enhanced physicals. I agree that in a pure H2H fight, Slade will take the majority, but it won't be through skill.
Even if Batman could win this fight, which he can't, since Bruce's skills can't compete with Slade's physicals, Bruce would STILL lose, since he'd never kill Slade. While Slade would have no qualms killing Bruce.