Deathstroke would be comparable to Taskmaster in combat, but in gladiator style with no prep time, the Spider takes this.
Winning Factors: Spider-sense, Speed & Agility, Super strength and we must notforget that Peter is a genius in his own right, so he'll try to get under Slade's skin with wit and insults, plus he has experience in web-slinging skill from impact webbing to even making a webbingshield that can take extreme heat.
Hmmm, I think I will actually have to give this to Deathstroke. Spider-Man is stronger, faster, more mobile, and has a monstrous Spider Sense, but I don't think it's enough to take down Slade. Deathstroke is one of the few comic characters better in hand-to-hand than Batman, as he is a master of predicting his opponents moves as they come. Deathstroke is also a better tactician and has a lot more lethal equipment than Peter, giving him a strategic edge in combat. Spidey may be tough, but he's not surviving a good blow from Deathstroke's sword. Add in Deathstroke's incredibly tough armor and enhanced reflexes, and Slade should be capable of lasting against Spider-Man in close range combat. Peter is no slouche in intellect or skill, but Deathstroke does outshine him in both categories. In a tough fight, I'd say Slade takes it through his own enhanced stats, better equipment, better tactical ability, better armor, and better skill prevailing in close range combat.