“昨夜西风凋碧树,独上高楼,望尽天涯路。”过片承上“到晓”,折回写今晨登高望远。“独上”应上“离恨”,反照“双飞”,而“望尽天涯”正从一夜无眠生出,脉理细密。“西风凋碧树”,不仅是登楼即目所见,而且包含有昨夜通宵不寐卧听西风落叶的回忆。碧树因一夜西风而尽凋,足见西风之劲厉肃杀,“