More than seven million viewers watched coverage of Tom Daley and Dan Goodfellow's Olympic bronze medal-winning dive.
The peak audience of 7.7 million was the biggest live TV audience for any event at the Rio Olympics so far.
The gymnastics final, which saw three-time Olympic medallist Louis Smith come off the pommel horse as Team GB narrowly lost out on a medal, attracted 7.2 million viewers.
Meanwhile, 18 million people watched the Olympics on BBC TV on Monday, for around 15 minutes in the day.
BBC Sport online also claimed a new record, with 15.2 million global browsers.
The record before the Rio Olympics was 14.6 million for England's match against Wales in the Euro 2016 football championship.