The Scot got the better of Novak Djokovic at Flushing Meadows in a five-set epic, ending a 76-year wait for a British slam win in the process.
Fred Perry was the last Brit to do so in 1936.
Rusedski, a former British number one himself, tasted defeat in the US Open final in 1997, and knew how much the victory meant.
"That was unbelievable," he told Sky Sports 1.
"If you look back, Fred Perry won his last major on September 10, and Andy Murray has won it on September 10."
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Rusedski went on to add praise for Murray`s coach Ivan Lendl, who like his player, had four failed final attempts before landing the top prize.
"Five finals like his coach and he finally wins one. That`s amazing," he said.
"At the end of the day he found a way to get it done and found a way to control his emotions.
"He can thank Ivan Lendl for that. You have to give him so much credit for what he`s done, to keep believing in what he`s done.
"It shows you what a champion he is and, having won this, he can go on to win many majors and maybe end the year as the British number one."
Mark Petchey, Murray`s former coach who commentated on the game for Sky, added: "I`m more thrilled he`s won it like this. It shows he`s unique and a bit special.
"It speaks volumes for Andy."
"It`s so special, I had this thought at match point, I was thinking of when I once played horseshoes with him at his house," Petchey recalled of his early days with Murray.
"You knew he had a touch of genius about him and I am incredibly proud. He had so much courage. We need to make the point that he elevated his game and he took it too Novak."
Former Davis Cup captain John Lloyd told BBC Five Live: "What a performance, that was just epic, a just dazzling performance from Murray.
"Mentally to come back from those positions - losing a two sets to love lead - how on earth did he do it?"