Demoman match-ups

From TF2 Wiki

Class			Threat	Strategy
Demoman	v	Scout	High	Scouts are difficult to kill as a Demoman. They can dodge and evade your Grenades and can run past your Sticky bombs if you don't see them coming. Your best bet to kill them is when the Scout slows down, which usually occurs during a CP capture or an intelligence grab. If they try to get in close, take advantage of the increased accuracy this gives you with your grenades; a grenade to the face should one hit a Scout, and the splash damage should severely injure him otherwise. If in one on one combat where the Scout won't slow down, sometimes switching to your bottle will yield better results.
Demoman	v	Soldier	Medium - High	Soldiers can be tedious to fight. At medium and long ranges you'll both probably be dodging as much as possible, and at close range you both tend to hurt yourselves. Overall, rockets are easier to control and harder to evade, and Soldiers have more health than you, so a slugfest favours them. Consider using your stickies to keep them at a distance. Their slow speed also makes them an easy and unwitting target for these if you have placed them in more subtle locations.
Demoman	v	Pyro	Medium	Pyros can kill you quickly if you're caught off guard, or while you are planting stickies. However, if you know they are coming, plant stickies on/around their path and detonate them when they come close. If you are already in flamethrower range you will not have time to detonate your stickies. Use your Grenade Launcher on them in those cases, as direct hits will be very likely inside flamethrower range.
Demoman	v	Demoman	Medium	Demomen use the same tricks as you. Try and hit them with your grenade launcher before they do likewise, or lay stickies under their feet. If an enemy Demoman had laid stickies all over the ground or against a wall, you can use one of your stickies to detonate near them and blow them away.
Demoman	v	Heavy	Medium - High	You can be one of the more dangerous threats for a Heavy. On the flipside, he can kill you quickly too. Try to get him while he's busy with something else, and approach him sideways or from behind. Then, lay some stickies behind him and explode them. With his slow speed, he oughtn't be able to run away. If he's - surprisingly - still alive, get out your grenade launcher and finish him. In a one-on-one fight, backpedal while firing your grenade launcher at him, and lure him into your sticky trap.
Demoman	v	Engineer	Medium	You can't survive close up head-to-head match-up against a Sentry (unless you're ÜberCharged or outside of their range). Your grenades and stickies are excellent at taking them out where they don't have line of sight or sufficient range. An added advantage is that your weapons will often take out the Engineer trying to repair them, too.
Demoman	v	Medic	Low	Medics are pretty quick, which makes them a little more difficult to kill. Try and hit them with your grenades, or juggle them with a few sticky bombs.
Demoman	v	Sniper	Low - High	Snipers will own you at long range. Try to get close, to lob some grenades and stickies from where they can't see you. This has the added advantage of allowing your team-mates to rush past without fear. Alternatively, use the long range launch of your stickies to lob them onto distant Sniper decks and wait for the Sniper to walk into blast range. Their threat level depends on how good they are as a Sniper. Snipers are also capable of shooting stickies away, putting your traps at risk.
Demoman	v	Spy	Medium	Spies can cloak to pass over your stickies. They usually place greater priority on Medics, Heavies, Engineers, and Snipers. Simply watch your back, especially when you stand still to place sticky bombs or lay down fire and Spy check suspicious team-mates occasionally. Most of the time, Spies will attempt to get in close to fight you. Bring out your bottle and scrumpy them to death. Two hits should do it.