There is no shame in losing to Novak Djokovic, the finest tennis player in the world right now, but the length of Andy Murray's face and his fuming demeanour after doing so told you how painful he finds it.
That is what happens when you feel you are one half of the biggest rivalry your sport has to offer, and the British No 1 was beyond consolation after succumbing in their seventh meeting of the season.
True to form, it was long and it was very close, but at the end Djokovic was fractionally the stronger as he won 4-6, 6-3, 7-5 before an O2 Arena full to bursting, leaving him top of their group at the Barclays ATP World Tour Finals.
Setback: Andy Murray was beaten by Novak Djokovic in the ATP world tour finals
Two hours and 34 minutes of protracted combat leaves the British player most probably needing to win his last round-robin tomorrow against Jo-Wilfried Tsonga - a straight sets victory would seal his passage - after the Frenchman lost in three to Tomas Berdych.
There were no such problems for Sheffield's Jonny Marray, who earlier combined with Fred Nielsen to beat second seeds Max Mirnyi and Daniel Nestor 7-6, 4-6, 12-10 to register their second win and guarantee a slot in the semi-finals.
It could, though, be another year when Murray fails to make the last four of an event that confirmed it would be staying in London until 2015, partly in his honour and partly because of the capital's insatiable appetite for top-class sport.
Of course, the forgiving nature of this format means he and Djokovic could yet meet again in the final next Monday night, but the indications are that Roger Federer will win Group B, and he will be the tougher opponent in the semis for whoever comes second.
Federer, playing on Thursday against the indefatigable David Ferrer, is keen to dismiss talk of the Djokovic-Murray contest being the pre-eminent one in the sport, and nowhere is he more likely to make the point than in an indoor environment.
The rapturous welcome Murray received from the crowd - noticeably more than on Monday - told of how eagerly anticipated his contests with the 25-year-old Serb have become.
Next year dislodging him from the world No 1 spot is high on the Scot's shopping list. But since beating him at the US Open, the evidence continues to rack up that this is going to be very difficult.
Out of reach: Murray's serve was formidable early on, but dropped off in the later sets
'The intensity of my matches with Novak has been extremely high this year,' said Murray.
'The last two minutes of today were probably what decided it. I need to make sure that regardless of how tough this loss was, I respond well in the next match.'
In what has been a breakthrough year for Murray, much has been made of his improvement but Djokovic has not stood still either.
The most startling aspect was that he came to the net 30 times compared to only seven visits by his opponent, who should be at least as good in that area.
The decisive point of the match was probably when the home favourite led 2-1 in the second and forced a break point, which Djokovic saved with a volley that shaved the corner. In the next game, Murray, now facing break point and perhaps not wishing to be outdone, suddenly decided to serve and volley and missed it by less than an inch.
Taking a tumble: Murray was eventually beaten 7-5 in the final set, despite breaking back
Tropical heatwaves hit Dunblane about as often as he chases his serve into the net.
'Those are the decisions you make, if they come off you're told you're a genius, if you miss them then you're an idiot,' reflected Murray in exasperated tone.
It was actually a pretty rash move that might have had a bit of machismo in it, part of a curious match which rarely saw both men at the top of their game simultaneously.
The British player started beautifully, breaking straight away and never having his lead threatened due to the consistency of his serve, which looked impregnable.
Had Djokovic been broken early in the second this would probably have ended up as an outstanding win, but the Serb is the ultimate competitor and he soaked up the pressure and drew ahead as Murray's serve deteriorated and the unforced error count rose.
The Scot was forced to hang on grimly until he broke back for 4-4, and he came within two points of victory at 5-4 before Djokovic again showed why he is No 1 by breaking a final time.
Wimbledon champions Marray and Nielsen again showed their liking for the big occasion in taking out the vastly experienced pair of Nestor and Mirnyi.
After clinching it on a second match point they are the first to go through, and despite being the lowliest qualifiers they have done it with a match to spare.