Sharjah qualified for the play-off after defeating Bangladesh's Bashundhara Kings 2-0, with goals from Luan Pereiran in the 45th and 71st minutes.
The win means Sharjah will meet Tractor next week for a spot in the group stage.
Tractor will host the Emirati football team at the Yadegar-e Emam Stadium in Tabriz on August 22.