If you look closely at the photo, you can see the head and ears hidden behind a branch. The antelope has a dark neck, so the photo is visually broken.
Good camouflage in the bush!
The sighting is from the fenced area of Punda Maria rest camp in Kruger. There is a small dense forest up in the hills with interesting birds and these antelope. It took me a lot of work to get at least some photos. Normally if an antelope is boarded in a camp, it grazes between the houses and you can come within 2-3 meters of it. Not these ones, I guess the way they live in the bush, hiding is innate.