The match was used by both sides as preparation for their upcoming Telkom Knockout Cup commitments next week.
Coach Pitso Mosimane's men will welcome Bloemfontein Celtic on Saturday while his counterpart, Cavin Johnson, will lead his troops against MTN8 Cup champions, Cape Town City, on Tuesday, October 23 at home.
In his starting line-up, Johnson fielded one of the most celebrated players in the Premier Soccer League (PSL), in the form of Siyabonga Nomvethe to lead his attack.
On the other hand, the Brazilians mentor rested his regulars and opted to use fringe players such as Thokozani Sekotlong, Aubrey Ngoma, Oupa Manyisa and Nathan Junior among others.
Under wet conditions in Durban, the visitors took an early lead through winger Lyle Lakay whose free-kick was deflected to beat goalkeeper Energy Murambadoro in the seventh minute.
Sundowns pushed for another goal and nearly doubled their lead through Ngoma in the 20th minute as he latched on a loose ball, but saw his effort blocked by Thapelo Nyongo off the line.
On the stroke of half-time, Nomvethe showed his quality when he beat Sundowns defenders on the left flank to set up Mhlengi Cele, who fired a low drive, but it went wide failing to trouble goalkeeper Reyaad Pieterse.
As they emerged from the tunnel for the second half, Usuthu dictated terms, and Nomvethe netted from the spot two minutes into the second half after Somila Ntsundwana was brought down inside the box by Wayne Arendse.
Usuthu fought hard to grab the lead, but Augustine Ramphela's shot came off the crossbar in the 51st minute.
It was Themba Zwane who restored Sundowns' lead when he was picked out by Brockie and guided the ball into an empty net.
Despite all the efforts from the Durban-based side, they failed to beat Pieterse in the closing stages, and the Tshwane side walked away with the trophy.