For easy / hard matchup, look up warwick guides threats.
Key differences:
- Warwick match up is not hard for you since you can knock up into full burst once E is on cooldown, and also if you can sustain yourself above 50% you are good!
- Warwick is stronger from 1-3, strongest at 1, while you are weakest at 1, stronger from level 4 (as in champion growth, you will not be stronger than warwick at level 4).

Key gameplay: sustain in lane until you can out sustain them from trade. (vs warwick force people out of lane and try to snowball.)

In lane: W (knock up) AA Q E(not full rage)
After titanic: W (knock up) AA Q Q(titanic auto reset) E(full rage)
1st combo give you full rage to heal at the end of the combo, while the 2nd give full rage before E, so 1st item difference is huge, good / bad reksai top experiencces will come down to how early you got your first item spike.

Champion suitable for people who like short trade / spacing / kiting back.

Source: Emerald 1 Vietnam "SHISHI0H#MILK".