The Messenger of Allah said: "Whoever catches one Rak'ah of the 'Asr before the sun sets, then he has caught it, and whoever catches one Rak'ah of the Subh before the sun rises, then he has caught it." (Using translation from Ibn Mājah 699)
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ «مَنْ أَدْرَكَ مِنَ الصُّبْحِ رَكْعَةً قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَقَدْ أَدْرَكَهَا وَمَنْ أَدْرَكَ مِنَ الْعَصْرِ رَكْعَةً قَبْلَ أَنْ تَغْرُبَ الشَّمْسُ فَقَدْ أَدْرَكَهَا»