The broadcast on Wednesday was the best-watched programme on the station this year as the audience peaked at 1.8 million and averaged 1.2 million.
It meant that almost a fifth of the entire nation tuned in to watch the historic game.
In ratings terms, the match outperformed top entertainment shows shown by the channel, including Britain's Got Talent. It was also one of the top 10 best watched football matches on STV over the last 10 years.
Elizabeth Partyka, deputy director of channels at STV, said: "Our sports team did a fantastic job bringing STV viewers dedicated coverage of the game and it's great to see that so many people tuned in to watch a thrilling match, even though we all hoped for a better result."