Darius and Renekton are completely different champions, how do you mean Darius does everything better than Renekton does?
Renekton can duel squishy top lane champs
very well since he can actually catch them with his dash, his Q is instant and his W does amazing damage when he has rage.
Meanwhile Darius since his rework nerfs has a VERY time dueling good early duelists
if he doesn't use his Q correctly. And even then many of these champions can actually bait it perfectly and trade with him while he is still casting it and cant retaliate. Then once he's used the handle of his Q on them for mediocre damage, he only has his heavily nerfed attack speed and his W for an auto attack reset. Any champ with a dash ability can then just walk away from him which forces him to use his pull which they then dash away from him.
Nevermind what Darius can do against ranged match ups, which unless the opponent messes up heavily, is pretty much nothing. At least Renekton has his dash to threaten them, and his Q can sustain from minions, right? Darius needs to actually needs to hit his opponent for that.
That aside, here's this - http://champion.gg/matchup/Renekton/Darius/Top
Statistically looks like Darius is Renekton's biggest lane counter at the moment, sucks for those who like picking Renekton blind Blue Side since Darius is flavor of the month.
However... http://champion.gg/statistics/#?roleSort=Top&sortBy=general.overallPosition&order=ascend
Renekton is actually a better pick overall, if only marginally. This may be because Renekton actually does much better than Darius does against other popular picks like Riven Fiora Gankplank Gnar Lulu and a few others.