Sam Querrey (1/2 to win semi-final tie on match coupon) has declared he was delighted with his performance to knock top seed Andy Roddick out of the Memphis Championships.

The American beat his compatriot 7-5 3-6 6-1 at the quarter final stage to set-up a semi-final clash with Latvian Ernest Gulbis (13/8 to win on match coupon).

World number 31 Querrey managed to combat Roddick’s infamous power serve, breaking it twice and managing to record 16 aces of his own during the tie.

He will face youngster Gulbis after the Latvian beat the fifth seed Tomas Berdych 3-6 6-3 7-6 (7-3) to secure his semi-final place.

Speaking after his defeat of Roddick, Querrey told reporters he had entered the game looking to take advantage of any mistakes his opponent would make.

“You’re not going to get that too many times from Andy, but I’ll take it,” said the 22-year-old.

“When that rare opportunity comes you’ve just got to take advantage of it. I thought I did a good job there, and just kept the momentum going and played an unbelievable third set.”

The other semi-final in Memphis will see sixth seed John Isner take on Philipp Petzschner (Isner 2/7 to win, Petzschener 5/2 on match coupon).