Sahih Muslim 608d

(30) – باب مَنْ أَدْرَكَ رَكْعَةً مِنَ الصَّلاَةِ فَقَدْ أَدْرَكَ تِلْكَ الصَّلاَةَ

(30) – The one who catches up with a rak`ah of the prayer, he has caught up with that prayer

This hadith has been reported by Ma'mar with another chain of transmitters.

وَحَدَّثَنَاهُ عَبْدُ الأَعْلَى بْنُ حَمَّادٍ، حَدَّثَنَا مُعْتَمِرٌ، قَالَ سَمِعْتُ مَعْمَرًا، بِهَذَا الإِسْنَادِ .

Sahih (Authentic)