It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:
"Whoever catches up with a Rak'ah of the Subh prayer before the sun rises, then he has caught up with Subh, and whoever catches up with a Rak'ah of 'Asr prayer before the sun sets, then he has caught up with 'Asr." (ES)
English reference (ES): Vol. 1, Book 6, Hadith 518 (ES)
Arabic reference (ES): Book 6, Hadith 522 (ES)