All-Stars James Harden, Julius Randle and Domantas Sabonis also had triple-doubles in victories by their teams, The Associated Press reported.
Antetokounmpo had 33 points, 11 rebounds and 11 assists to help Milwaukee beat Washington 125-119. The two-time MVP helped the Bucks overcome 42 points, 12 assists and 10 rebounds by Westbrook, who owns the NBA record with 42 triple-doubles in 2016-17.
Triple-doubles have since become more common – he averaged one for three straight seasons – but there had never been so many as during Saturday's eight-game schedule.
Randle started the record day with 26 points, 12 rebounds and 12 assists in New York's 119-97 victory in Oklahoma City, becoming the first Knicks player with two triple-doubles in the same season since Mark Jackson in the 1988-89 season.
Harden had 24 points, 10 rebounds and 10 assists, his ninth triple-double since being traded to Brooklyn in January, as the Nets beat Detroit 100-95.
Sabonis got the last of the night with 22 points, 13 rebounds and 10 assists to lead Indiana to a 122-111 victory in Phoenix.