"Andy will be disappointed and will feel he could have done more in the latter stages of the match, and Laura will be disappointed with the double faults towards the end of the match, but this will still go down as a great day for British tennis."
The British pair had to settle for silver - Team GB's 35th medal of the Games - after going down 2-6 6-3 10-8 to the top seeds from Belarus.
Lisa Raymond and Mike Bryan of the United States won bronze with a 6-3 4-6 10-4 victory over German pair Sabine Lisicki and Christopher Kas.
Murray and Robson had only previously paired up at two exhibition events and were competing together at London 2012 on a wildcard.
Just hours earlier, Murray overwhelmed Roger Federer to complete the biggest triumph of his career.
But his hopes of double gold were ended by top-quality opposition on Centre Court.
Azarenka and Mirnyi are not only top of the mixed doubles rankings but women's singles world number one and men's doubles world number one respectively.
It looked as though a major upset was on the cards when the home duo broke serve twice before Robson impressively served out the first set.
The 18-year-old was dominating at the net and from the baseline, but Azarenka and Mirnyi managed to strike for a 3-1 lead in the second set and stayed calm to level the match.
The Belarusians made far fewer errors in the champions tie-break and although Murray saved two match points, there was no stopping an Azarenka smash on the third.
Robson is the third-youngest female tennis medallist in Olympic history.
Andy Murray could not add the Olympic mixed doubles gold medal to his men's singles title as he and Laura Robson lost to Victoria Azarenka and Max Mirnyi.