"I did not play well in the first set, I did not play well in the second set," a despondent and somewhat testy Murray said afterwards, blaming the lack of the bounce on the damp Newport court for disrupting his rhythm.
"I know that the next time I lose like that I will see what I'm doing wrong and what shot I need to work on. Today I can't see because I [could not] play properly."
Despite the poor bounce, Murray started well enough, serving and returning fluidly despite the conditions. He also showed remarkable speed across the court - on one occasion reaching a fast-dropping ball to play a winner that was breathtaking.
But Dupuis, aged 31 and ranked 111 compared to Murray's 213, was never going to be an easy opponent and he was able to break Murray in the 10th game to take the first set.
In the first game of the second set, Murray had three chances to break Dupuis' serve but failed to push home the opportunity. From there, the teenager never recovered his rhythm and lost the next two games as he looked out of sorts. Even hurling his racket onto the ground - something he says helps motivate him - did not help to turn things around.
While he certainly never gave up - he made a fantastic effort to come back from 40-0 down in the fourth game to win it - from that poor start it was always going to be a huge task to secure a victory. Dupuis wrapped up his win in little over an hour.
Asked whether the court or his play was to blame for his defeat, Murray said: "This was the worst type of court for me to play [on]. I could not play the way I like to play because the ball was bouncing so low and it's difficult to rally from the baseline. Obviously, returning is one of my weapons and because the ball was not bouncing I could not get any rhythm to my return."
Before the match, Dupuis had talked of the merits of his experience versus Murray's youth - saying there were advantages to both. Afterwards he said Murray's frustration had been obvious during the match.
But despite what Murray may have said, this will likely have been part of a hugely important learning curve - not only for him but for those pundits who, since his success at Wimbledon in coming from nowhere to reach the third round, have unfairly built up the expectation surrounding him.
His coach, Mark Petchey, has said that these sorts of tournaments, away from the glamour of the All England Club in SW19, must become Murray's bread and butter over the coming year for him to gain the experience he needs to develop his full potential. Murray next switches from the Atlantic to the Pacific, travelling to California for the first of four Challenger tournaments before a possible entry in the US Open in August.
"At Queen's and Wimbledon I showed I can play with some of the best players in the world," Murray said. "When I go to play in the Challengers, I will certainly have a lot more belief in myself."
Greg Rusedski, last year's winner, won his second-round match 6-2, 7-6 against Robin Vik, of the Czech Republic. Rusedski now plays Dupuis in the quarter-finals.Reuse content