Andy Roddick became the first player to qualify for the quarter-finals of the Shanghai Masters on Thursday after an impressive 6-3, 6-4 win over Nicolas Almagro of Spain. Playing under the closed roof at the Qi Zhong stadium, 10th seed Roddick secured a single break in each set, wrapping up victory with his 11th ace in a controlled display that saw him make just 14 unforced errors. The victory over the seventh seed for the 29-year-old, with one title to his name this year, comes after tougher tests in the first two rounds, where he beat Taiwan's Lu Yen-hsun and Grigor Dimitrov of Bulgaria. Roddick said his serve had worked well after he made an adjustment in the warm-up. "As far as the way I've been hitting the ball and playing, it's been OK but the serve's been up and down. My percentages weren't where I wanted them to be," he said. "And I was going like in spots where I'd make three serves in a row, but then miss four or five. It's those gaps where you're hitting second serves where guys get a look. "I cleaned that up a little bit today. I think that makes everything look a little bit better. Then you go 2-2 on breakpoints, it makes it look pretty straightforward." Elsewhere on Thursday, Australian teenager Bernard Tomic was beaten by 12th seed Alexandr Dolgopolov 7-5, 1-6, 0-6. Top seed Rafael Nadal will later face 15th seed Florian Mayer of Germany and Britain's Andy Murray, the number two seed, plays Stanislas Wawrinka, the number 13 seed.