CC Antya 14.17

eka-dina mahāprabhu kariyāchena śayana
kṛṣṇa rāsa-līlā kare, — dekhilā svapana
Word for word: 
eka-dina — one day; mahāprabhu — Śrī Caitanya Mahāprabhu; kariyāchena śayana — was taking rest; kṛṣṇa — Lord Kṛṣṇa; rāsa-līlā kare — performs rāsa-līlā dance; dekhilā — He saw; svapana — a dream.
Translation: 
One day while He was resting, Śrī Caitanya Mahāprabhu dreamed He saw Kṛṣṇa performing His rāsa dance.