Best Character to use when playing one on one in DotA

You'll have more advantage using a range character especially if you're up against a melee one. You can harass your opponent with cheap shots thus making you gain more money than him which will also make you stronger since you will be able to complete your items first before he does. You will also gain level faster than him because he needs to recharge his life because you're harassing him often. Viper is the best when playing one-on-one, if your opponent is melee just get 4 blade mails and victory will surely be yours.