Thabang Sibanyone scored in the 28th and 62nd minutes at Makhulong Stadium in Tembisa as the young Brazilians moved to 15 points from six matches.
Sibanyone has now scored five goals for Sundowns and is the leading scorer in the MDC.
In the other early kick-off, Bloemfontein Celtic beat Bidvest Wits 2-1 thanks to two quick goals from Tumelo Mangweni around the 70th-minute mark after Somila Ntsundwana had given the Students a 52nd-minute lead.
Kaizer Chiefs take on Highlands Park at 12h00. The game is live on SuperSport 4. The Lions of the North can take over from Sundowns at the summit of the table if they beat Amakhosi.
Sundowns Reserves vs Arrows: Mpho Mathekga, Rheece Evans, Motoro Monyai (c), Motjeka Madisha, Sibusiso Khumalo, Lukhele Mdluli, Keletso Makgalwa, Flavio Bento, Eric Ntlaba, Musawenkosi Mdhluli, Thabang Sibanyone
Subs: Abram Mgcono, Thabang Chuene, Thamsanqa Masiya, Mkhuma Promise, Tlotlo Leepile