The Messenger of Allah ﷺ said, "Whoever completes one rakat of Asr before the sun sets has performed it in time, and whoever completes one rakat of Fajr before the sun rises has performed it in time."
وحدثناه عبد الأعلى بن حماد حدثنا معتمر قال سمعت معمرا بهذا الإسناد