The boxers will meet in the semifinals of the World Boxing Super Series tournament on January 27, an Ukrinform correspondent reports.
"Preparation is almost over. I'm ready for the fight. I would like to ask Ukrainians, if they can, to come to Riga for our fight. I will talk to you after the fight," Usyk said at a press conference after the training.
The open training session included intensive warm-ups, as well as a sparring with coach Serhiy Vatamaniuk.
Several hundred Latvian fans, including representatives of the Ukrainian diaspora, attended the event.
The bout between Usyk and Briedis will be held in Riga at 19.15 Kyiv time on January 27.