Masai will lead the international challenge against a strong South African field as more than 10 000 runners are expected to take part in the race, which starts at the Sir George Grey Street exit of Grey College and finishes at Kings Way in Mangaung at 7am.
The Kenyan will be hoping to end the series on a high note after making his debut in the competition at the Durban leg, where he finished ninth in a highly competitive field.
He clocked an impressive 28:13 and was full of praise for the organisation of the race.
Masai is now looking forward to another opportunity to test himself against some of the country's best distance runners, with his sights firmly set on a place at the top of the podium.
The Two Oceans Half-Marathon winner has enjoyed his time in South Africa, particularly during his stay in Cape Town, and says the country has become a home away from home for him.
“I really enjoyed training and racing in South Africa. I received a warm welcome. The Run Your City Series is world-class,” Masai told SABC Sport.
The East African star arrives in Mangaung in excellent form after setting a personal best of 27:19 at the Prague 10km Night Race last month.
His performance in the Czech Republic gave him the confidence to return to South Africa and take another shot at victory in one of the continent's premier 10km road-running series.
Masai believes he has what it takes to challenge for the title and is eager to turn his strong performances into a memorable victory in the Free State.
“I'm very happy with my results in Prague. After that PB, I knew that I would be focusing on the Mangaung 10km race. I'm looking forward to giving a good performance and being on top of the podium,” he added.
However, Masai will have to overcome a determined local challenge if he is to achieve his goal.
South African Kabelo Mulaudzi will be keen to finish the year on a high after defending his Run Your City Joburg title.
Mulaudzi has established himself as one of the country's most consistent road runners and will be eager to spoil the Kenyan's ambitions.
Another runner to watch is Zenzile Pheko, who has produced impressive performances with back-to-back second place finishes in Tshwane and Johannesburg.
The series has already delivered exciting races this year. Adriaan Wildschutt won the opening leg in Gqeberha, while the Cape Town race was cancelled because of severe weather conditions. Olympic champion and world-record holder Joshua Cheptegei claimed victory in Durban before Salem Kibet triumphed in Tshwane, with Mulaudzi taking the honours in Johannesburg.