Mphela scored from a close-range shot and a penalty in the second half as he raised his goal haul to five in three matches since ending a training boycott triggered by the refusal of Sundowns to grant a transfer request.
His second goal gave Sundowns a 3-0 lead after 73 minutes in mid-afternoon heat only for Arrows to hit back through a Collins Mbesuma shot that took a wicked deflection and a own goal by defender Thapelo Tshilo. Zambia-born former Portsmouth striker Mbesuma had a chance to equalise in stoppage time only to be foiled by a wild, last-ditch clearance as the five-time champions clung to the three points.
Sundowns moved within two points of inactive leaders Orlando Pirates, while Kaizer Chiefs and Ajax Cape Town share third place. Pirates face a difficult away fixture at Bloemfontein Celtic tomorrow and Ajax are expected to collect three points when they host bottom side Mpumalanga Black Aces.
Chiefs salvage draw
Siphiwe Tshabalala, who scored the first goal of the 2010 FIFA World Cup in a draw with Mexico, salvaged a 1-1 home draw for Chiefs against mid-table Free State Stars through a close-range shot four minutes into stoppage time.
Free State upset Sundowns recently and were on course to cause another shock when substitute midfielder Madoda Motha headed them in front off a corner with just four minutes left. But after repulsing a late Chiefs onslaught, Stars left Tshabalala unmarked and the midfielder gave Zambia goalkeeper Kennedy Mweene no chance with a well-placed rising shot.
There was other late drama with Lehlohonolo Majoro converting a 93rd-minute penalty to earn AmaZulu a 1-1 draw against Wits University. Sifiso Myeni gave Wits a late lead only to be denied maximum points by Majoro.
Musa Nyatama struck on 91 minutes to give Maritzburg United a 2-2 draw with Vasco da Gama. Maritzburg clawed back after conceding two first-half goals to snatch a precious point and stay three points above second-last Swallows.
The matches between Platinum Stars and defending champions SuperSport United and relegation-threatened Moroka Swallows and Santos offered less excitement petered out to goalless draws.