The second seed cantered into the second round with a simple straight sets win over Taiwanese Yeu-Tzuoo Wang on Thursday before reliving his horror of appearing on the television show last week.
The A-Rod's stumbling block proved to be a question of livestock.
When asked to name the letter of the alphabet that sounds like a female sheep, the man with the world's fastest serve faltered.
While the audience chuckled and mouthed 'ewe' to each other, Roddick scratched the side of his dishevelled hair before calling out 'Baaaa'.
"I had no idea, man," he said unnecessarily. "But you know what, I knew going in that my ignorance was going to shine through.
"I was just happy it happened later rather than sooner.
"Oh, I was nervous. I was very nervous. You know, you would be shocked at the stuff I don't know," he laughed. "But it was interesting."
The American said that Ms Robinson's schoolma'am-ish delivery had thrown him.
"I couldn't understand her accent half the time," he said. "She talks fast, and I'm thinking... I'm thinking she's going to like make fun of me or something.
"But you're right, there's not much excuse."
"You guys think you're clever with your livestock questions," he laughed. "I've heard it six times already... anything you guys are coming up with, yeah."
