Go ask KT Rolster.
I was actually just looking at the LCK records. I don't quite understand how KT Rolster didn't qualify for worlds.
KT Rolster 3-0'd SKT in their latest face off.
Each team finished the regular season with a 13-5 record (ROX Tigers had a 15-3 record for first place). SSG qualified via winning regionals (over KT Rolster in the final). Not sure how it was decided that KT Rolster had to play that final though, and SKT got the bye to worlds, when they had the same record and KT Rolster had a winning record on them.
To be fair, I never followed the LCK though. I don't know what their rules are or how these things work.
In the two playoffs, SKT came 1st and 3rd while KT Rolster came 3rd and 2nd. Maybe that's why (although in NA I think the summer playoffs are worth more points).
Nonetheless, back to your point, KT Rolster seemed to have SKTs number during the regular season. If someone wants to beat SKT, that's probably where they should start.