Gaudio2004
Semi-Pro
Murray AO 2010**
Not 2011, if you take Djokovic's whole year into consideration. More 2010 final considering Murray had Federer's cards checked in all the years before in ATP tournaments and was playing (imo) his best tennis. So many chances to win the third set, but more importantly break points in the first two sets too.
Federer destroyed Murray in the second set - that Murray kept it to one break was astonishing, he earned one break point in the second set against Federer's serve, Federer had break points on all of Murray's service games bar 1.
First set Federer was also the better player; he took the initiative early and made the early break, Murray broke back despite Federer controlling the rallies and moving him.
What was the result of that? Even when Murray was 5-2* ahead in the third set, it was still Federer who was the aggressor, he found his range and Murray paid.
I don't think AO 2010 was Murray's most heart-breaking loss. He was thoroughly outplayed in both AO2010 and AO2011 finals in my view.
In AO2011 by the way, he had break points at 5*-4 (I think) to take the match from 5-0* to 5-5*, Djokovic saved them however and won the match in that game.