Ubaidullah b. Mu'adh reported it on the authority of his father Shu'ba with the same chain of transmitters and he made this addition. He made a mention of these two names but I do not know whose name he mentioned first.
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، بِهَذَا الإِسْنَادِ وَزَادَ قَالَ شُعْبَةُ بَدَأَ بِهَذَيْنِ لاَ أَدْرِي بِأَيِّهِمَا بَدَأَ .
Muslim
The Book of the Merits of the Companions • Hadith 169