Stellenbosch picked up their first win of the PSL campaign this weekend, as Cape Town City also grabbed three points.
Mendieta celebrated his first start for Steve Barker’s manne with a 21st-minute opener before Zambian ace Sinkala clinched a historic first victory for the Bolanders at the Danie Craven Stadium with a 2-0 win over Chippa United.
The three points lifted Stellies to ninth in the standings on five points.
Meanwhile, City moved into fifth place with their 4-2 win over Bloem Celtic in a humdinger at Cape Town Stadium on Sunday.
In-form midfielder Mdu Mdantsane continued his scoring streak this season with third in as many matches, getting the opener after 17 minutes.
Fagrie Lakay gave them a two-goal cushion when he scored from the penalty spot after 39 minutes, before Celtic hit back from 12 yards out through Ndumiso Mabena.
Thabo Nodada restored his team's cushion just before the break, but the MTN8 finalists weren't given up and pulled one back through Menzi Masuku.
But Nodada made the nommer vas with 12 minutes to play with his second of the match.