What facts is "countering" based on?

I main Darius in the top lane so I run into the occasional Teemo. According to some champion select websites, I am being "hard countered", meaning I will have a very hard time in lane.

The thing is, I don't have any problems whatsoever playing against Teemo (in fact, I do a tiny cheer of joy knowing I can smash that little devil into oblivion). Some might say that a main Teemo player (Satan?) might have an easy time against a Darius since he can outpoke Darius.

Now this would be an endless debate of summoners and skills. I'll keep my question as broad as possible:

On what basis do these websites state that champion A counters champion B?

On what facts does countering a champion work? It seems like this is your question which doesn't make complete sense to me but I'll have a go anyways. One thing you need to keep in mind is that those websites are crowd sourced and so are unreliable. Also, keep in mind that when champions are counters there is usually something specific about the champion that counters the other. In low ELO a teemo will likely just try to auto Darius repeatedly taking minion aggro, losing farm, and not try to kite away from his grab. In high ELO Teemo will use bushes to avoid taking aggro and do a lot of hit/run feints so that he doesn't get grabbed easily while poking Darius down and denying him farm.

keep in mind that when champions are counters there is usually something specific about the champion that counters the other. This statement I made in the last paragraph is the most important. As a Poppy player I'll use her for example. One of my biggest counters is Darius. Why does he counter me? Well Poppy has a passive that reduces burst damage. Darius can bleed Poppy which does low damage and doesn't get reduced by her passive. Darius's ult also ignores Poppy's passive since it does true damage. This means that any trades they make Darius will win out because Poppy's greatest tool for reducing damage is negated. After the trades Poppy can't easily walk away because Darius can grab her and prolong the trade even more. This makes it EXTREMELY dangerous for Poppy to try to farm minion waves at all levels. Another example, Poppy vs Irelia. Irelia counters Poppy because she is more of an AA champion who does true damage and can slow/stun. If Poppy is winning in a trade, Irelia gets a free stun to prolong free damage and has an ability that does true damage. Rumble counters Poppy because she can safely burn Poppy with the low amounts of fire damage which don't get reduced by her passive.

I'll look at another specific counter. Everyone knows that Trundle is a counter to Renekton but if you try to fight Renekton as Trundle early you will lose. Early game is simply about focusing on farming/sustaining as Trundle in this matchup. The reason Trundle counters Renekton is that Trundles ult essentially gets stronger from Renekton's ult. Renekton gets bonus health and Trundle simply steals that bonus health along with armor/MR on top of that. If you are the Renekton player going into this matchup and understand the counter you will realize that the first item you want to rush is a damage item. That's because if you get tanky first you are simply spending gold on stats for trundle to steal.

Essentially, in order to counter Poppy you use a champion who doesn't get reduced damage vs her passive. You can apply this to other champions. If they have a strength that is negated or a weakness they can exploit by picking a champion, it's generally considered a counter in a broad sense. Keep in mind that all counters aren't equal though. You might pick a Riven to counter a Gnar.... but a good Gnar player will understand what makes Riven beat a Gnar in lane and focus on negating that advantage to make the lane more even.

Many people will pick a champion against another simply because they want to counter them. The problem with this is that they won't understand what it is about the champion that counters the other champion and the way they play them won't actually be a counter because they don't understand reasoning for the counter.

One,Counters DOES NOT mean you will lose if you play against one no matter what. You can go zed into Fizz and still win EASILY. It's not that , but also how you can outplay the champ, Teemo can only kite and poke . Darius can go heavy aggro and easily gank teemo pre 6 . At bronze-gold elo , You can win that match up with just straight up brute force. Your a darius main? More than another reason why you would win lane without even noticing. The reason why they say its a hard counter because its the strongest way to stomp darius ( By playing like teemo) now that DOESN'T mean you can't outplay your own counter pick . Then again , In high elo like d3-challanger , There are a few teemo mains that still get rekt by Darius all day . The way a teemo should beat a darius is easily is getting E first then Q . Never take w and Shroom across from darius and make him run into it. Of course with darius bleed + Ignite There's almost a high potential of killing .

How to Beat a Darius as teemo = In low elo people tend to just poke their way into winning lane while tanking minion aggro and missing cs. In exchange kill over farm. In high elo (trust me , im master tier and I've seen this almost all the time). They usually try to waste your flash as soon as possible by going stealth at level 4 and freeze lane infront of him . While doing so , at levle 6 , Plant shrroms infront of your minions and freeze there . CS Denied. Kill potential Denied. And a roaming Darius isn't that scary tbh so its k to be top all day .

How to beat a teemo as Darius = In low elo people just get dorans blade/Shield and just spin close to the target and drop him low as low as possible. In high elo , most of time , You'll see them get Long sword and 3 bots and rush a early brutulizer because of the CD , Most of them usually max at w before teemo hits 6 so he wont be able to move fast and kite you away.

It's all mental work. You know how to play a champ . Outplay him with just logic. The site I usually use is http://elohell.net/league-of-legends-champions/ Not all counters work , remember that.

The matchups just seem to go off votes, people upvote champions they think work well in that matchup and downvote ones they think do not. In this case Teemo has 23 thousand upvotes and 11 thousand downvotes while kayle has 7 thousand up and 2 thousand down.

Essentially it's an opinion poll asking thousands of players who has the advantage on the match up. It's very simplistic as it cannot take into account skill levels (for example some champions are very strong at higher ELO but not so much at lower ELO) and may take time to update after nerfs or buffs but it still gives you a rough idea of what people think of the matchup.

In Teemo vs Darius the problem Teemo has is that his auto-attacks are the same range as Darius's Apprehend. That makes it really hard to poke hard enough to take down Darius, especially once Darius gets to the point where a single catch chunks out most of Teemo's health or even kills him completely.

Teemo does have an early harass and poke advantage though, if he can maintain that lead he's fine.

It all relys on submissions and their votes (crowd sourced).

is it a reliable source?

well that depends: i always say "knowledge > skill > counter". I recommend playing LoL without visiting that site ever and ignore the chat in champ select that contains the word "counter".

My Opinion:

If you see X counters Y, this means X can punish Y easier for his mistakes. But a good Y player will reduce his mistakes to a minimum.

All the stuff on this site is a summarization of many peoples opinions and experiences and it's up to you if you believe them!