Among the Sanqing disciples, even if there is only one disciple, they are still eligible to compete for the Ghost Dao opportunity. After all, this Ghost Dao opportunity belonged to the entirety of Sanqing, not just to Yu Qing alone.
Given this, as a direct disciple of the Upper Qing Saint, Jiang Chen naturally had the qualifications to compete for the opportunity with the Yu Qing lineage. Even the grand master of the Taiqing lineage, if he wished to compete, was also eligible.
The Primordial Heavenly Sovereign was cornered by the Upper Qing Saint, and with his thick skin, he couldn't say in front of both Upper Qing and Yu Qing that the Ghost Dao opportunity solely belonged to the Yu Qing lineage.
All disciples under Sanqing had the qualifications to vie for this Ghost Dao opportunity. One might even say that whoever acted first would claim it.