CC Antya 7.18

sarva-śāstre kṛṣṇa-bhaktye nāhi yāṅra sama
ataeva ‘advaita-ācārya’ tāṅra nāma
Synonyms: 
sarva-śāstre — in all revealed scriptures; kṛṣṇa-bhaktye — in the devotional service of Lord Kṛṣṇa; nāhi — is not; yāṅra — of whom; sama — equal; ataeva — therefore; advaita — without a competitor; ācārya — ācārya; tāṅra nāma — His name.
Translation: 
“He is unparalleled in His understanding of all the revealed scriptures and the devotional service of Lord Kṛṣṇa. Therefore He is called Advaita Ācārya.