Andy Roddick of the US and his coach Jimmy Connors (R) attend a practice session at the Kooyong Classic tennis tournament in Melbourne January 10, 2008. (Xinhua/Reurters Photo)
However, he didn't appear to be missing the services of his coach too much, closing out the match against Nadal with one of 17 aces, and had multiple service winners against the Spaniard.
One of his aces measured 241 kph, breaking the Dubai serve speed record he set a day earlier.
"I knew I was going to hit it well, from the first point. I kind of let it fly, and that's what it took tonight," said Roddick, "Anything less than that and I wasn't going to win."
Roddick will next face third-ranked Novak Djokovic, who beat Igor Andreev 6-2, 6-1.