Hello since the release of Diana all my games have been disastrous, her Q hits really hard and has high ap ratio, her ult refresh thingy is really lame and she has a lot of hp per lvl and high hp in general. So how do i beat her in mid/top? i have tried vladimir and gragas both beaten extremely easy. How do i counter Diana? I´ve been on verge of staying out of the league because of this op champ.

P.S why do people always downvote comments even if theres nothing wrong with it?

You counter Diana by beating her very early. Wukong, Renekton and Darius are the champions I have succeeded with in top lane. Also spending lots of time in brush makes her want to use her Q blindly and if she missed, capitalize on it, IMMEDIATELY! LeBlanc and Kassadin absolutely **** on her mid and Karthus, Morgana and lux counter her with their range and safety meaning she can't snowball. Also say SS and ping the **** out of team-mates is she goes missing because she snowballs so efficiently.

The trick to countering a champion is learning to play the champions that you like, so vladimir and gragas would be, try playing vladimir as a Tanky-mage with rylai's crystal scepter, mercury treads, spirit visage, etc. Make sure you have 4 stacks on your E for maximum damage and ignite her after you use ur ulti. Get as much farm as possible. If you feel she's escaping from you or has attack speed buy a randuin's omen.

With gragas he's a complicated champion but I'd recommend a tanky hybrid build with items like rod of ages, lichbane, hextech gunblade and possibly a rabadon's deathcap. Make sure you do stuff like throw your Q out and when she walks away from it throw your R at her so she lands right next to your Q then explode the Q and body slam her (activate W before any of this happens). Her attack speed will be slowed by your Q so don't mind her passive.

people here said everything i guess.
Analye enemy-champ before u want to counter him.

Diana:
-in early squishy/medium health
-snowballs like a boss
- is an assassin so if the q hits u, u wont get away that easy.

so now try to counter it:

1. Defensive playstyle:

If u wanna play defensive u need very high lane sustain, though its not easy to dodge the Q of diana. Vlad with his great dodge spell , or galio cause he's fkn tanky, should be a good choice.

2. Offensive playstyle:

If u wanna go agressive vs diana u need a champ that can snowball better or snowballs the same and has more sustain. it's getting a bit difficult here.
u could play Katarina (harass Q, and jump out of her Q with E) or maybe vlad (hes getting health back. diana isnt) . I personally favorise Akali. Why?
Because Akali's Q->hit comb is one of the best snowballs in early. and with W spell u can get invisible so she will often fail her Q and even if she hits u can get away. I use runes+ masteries to get + 10 ad so i have 8& spell vamp (akalis passive) by spamming Q i regenerate a lot of health and do lasthits. U surely need some skill to dodge and stuff, but since youre lvl5 your Q does so much dmg and gives you some health back. Diana cant spamm her Q in early, cause she will get oom quickly if she does.

Anyway Diana is a very strong champ and should be not underestimated. If she gets some kills or chances in early, she can truly get OP, like other Assassins.