Elise Mertens and Taiwanese player Su-Wei Hsieh won the women's doubles final of the WTA 1000 tournament in Indian Wells.
Belgium came 29th in the medal rankings, with seven podium finishes.
Belgium had been waiting 45 years for a medal in one of the equestrian disciplines on the Olympic programme.
Bashir Abdi drew on the last of his physical resources to give Belgium a seventh Olympic medal. Koen Naert, another Belgian, finished in the top 10.
Already an Olympic champion in Rio in 2016, Nafissatou Thiam confirmed her title at the Tokyo Games by winning gold in the heptathlon.
The Red Lions started as favourites. They have embraced their status with flying colours and have won their first Olympic title in this popular team sport.