Lesotho’s Kamohelo Mofolo won in 27:58 ahead of Kabelo Mulaudzi in 28:01, with Mosiako just two seconds back to secure the final podium spot.
For the 30-year-old, it was more than a medal — it was proof that his career is firmly back on track after a frustrating spell with injuries and loss of form.
“I am super excited and happy with the outcome – finishing in the top three after so long is really amazing for me," Mosiako told SABC Sport.
"Running 28:03 after such a long time, I’m over the moon. It’s been tough for me this year.”
The Nedbank Running Club star added that his victory at the South African Half-Marathon Championships earlier this year had already sparked a turning point in his career.
“Winning the SA half-marathon title brought back my confidence and changed how I approach races. I’m happy with how my preparations are going, and today’s race gave me a good indication," he noted.
"It got a bit tough after 5km, but I managed to hold on."
At next month's Cape Town Marathon, Mosiako will be facing a strong field, including three-time winner Stephen Mokoka and former national marathon champion Elroy Gelant.
This is set to be only his second career marathon, after his debut in Abu Dhabi last year, but he remains confident that he can make a statement.
"The preparations are going well. Maybe I’m a little too fast right now, like a jaguar," he joked.
"And I might need to put in more long runs to balance it out, but if my body feels good, and the weather plays along, I believe I can run a sub-2:09 in Cape Town."