I mean Gasquet would have lost in the QF to Nadal nonetheless, but Murray had yet to make a GS QF and the idea of him being behind near enough all the youngsters he was compared with (Djokovic miles ahead, Baghdatis made a slam final, Gasquet and Monfils semi finals) so that game he broke Gasquet back serving for the match was the most important game of his career I would say.
Gasquet at the time had played very well at Wimbledon 2007 against Roddick in particular, and made the WTF that year, but a loss to Nadal who was at his peak form that summer would have been accepted. To lose from 7-5 6-3 *5-4 up to a guy he beat in the two previous matches and seemed to be ahead of up to that point, was a killer blow for him.
To Murray it led to a first win over Djokovic in the Canada QFs, a repeat win over him to win his first MS a week later at Cincy and the USO final. Both guys' paths were never the same again