The top champs out of lane to counter Rek'Sai include Ziggs, Samira, and Kai'Sa. These are all good at countering Rek'Sai with win rates over 62%. Even if these Rek'Sai counter picks are not chosen in your lane, it's not a good idea to choose him into these matchups. They will usually win against Rek'Sai.
Conversely, if the opposite team choses either Taric or Tahm Kench, you should strongly consider picking him, as he easily wins against these champs with win rates over 51% against both ofthem.
methods2.text1
methods2.text2
methods2.text3
otherMatchupsDescription