Nare claimed her third victory of the six-series in 32:44, ahead of her compatriot Gebre in second in 33:08, while three-time Spar Grand Prix champion Van Zyl completed the podium in 34:14.
Nare took advantage of the absence of Johannes – who won bronze for Namibia in the marathon at the Commonwealth Games underway in Birmingham in the UK, a week ago.
The 41-year-old Johannes won the opening race in Gqeberha, and came second on both occasions at the Durban leg on June 26 and Mbombela on July 16.
Gebre finished third on the three occasions.
The Tshwane Grand Prix at the Irene Agricultural Centre was the first since the start of the Covid-19 pandemic to be run on a circular route rather than a loop.
The route started off on the research farm before taking the runners through the campus and back to where it started.
Nare and Gebre went into the lead immediately, with Xaba hot on their heels.
However, Xaba dropped back at about 5km and Van Zyl gradually reeled her in 400m before the finish en route to a third place finish.
Van Zyl said the route suited her perfectly:
“I have been struggling with a foot injury and a couple of bouts of flu, so I ran according to my fitness level. I didn’t push too hard at the start.
“I still had some gas in the tank at the end of the race, and I was able to overtake Glenrose. I hadn’t expected to come third, so I am really happy.”
According to the race organisers, Johannes was unable to change her flights to enable her to reach South Africa in time to take part in the Tshwane race.
The next race will take place in Johannesburg on October 2, while Cape Town will host the final leg on October 23 in the chase for the R190 000 grand prize purse.
Winners at each race get R30 000 and 20 points for the victory on the leaderboard, which ultimately determines the rankings.
(Top 10 with their clubs in brackets)
1. Tadu Nare (Nedbank) 32:44
2. Selam Gebre (Nedbank) 33:08
3. Irvette van Zyl (Nedbank) 34:14
4. Glenrose Xaba (Boxer) 34:28
5. Kesa Molotsane (Murray & Roberts) 34:52
6. Diana-Lebo Phalula (Boxer) 35:25
7. Cacisile Sosibo (Boxer) 35:38
8. Kyla Jacobs 35:48
9. Caroline Mhandu (Maxed Elite) 36:11
10. Patience Murowe (Nedbank) 36:25