The first semifinal series from the League of Legends LCS Lock In 2021 saw Cloud9 face off against 100 Thieves in a nail-biting best-of-five series.
- League of Legends Spring 2021 LCS Lock In first semifinal: Cloud9 stages massive comeback to defeat 100 Thieves – Sportskeeda
- Cloud9 reverse sweep 100 Thieves, advance to LCS Lock In finals – Dot Esports
- Cloud9 advances to the LCS Lock In Finals, taking down 100 Thieves in a reverse sweep – InvenGlobal
- LCS Lock In Semifinal Preview: Cloud9 vs 100 Thieves – The Game Haus