Chapter: The one who catches up with a rak`ah of the prayer, he has caught up with that prayer
Abu Huraira reported: The Messenger of Allah ( صلی اللہ علیہ وسلم ) said: He who finds (gets) a rak'ah of the afternoon (prayer) before the setting of the sun, he in fact gets (the full prayer), and he who gets a rak'ah of the morning (prayer) before the rising of the sun he in fact gets (the full prayer).
Authentic