The Thornhill, Ont., native hit 20 aces in just under two hours against the 2010 Wimbledon finalist, notching 33 winners and breaking Berdych three times.
"It was a good match for me. I did a lot of things well, and I'm happy with the way I closed it out after I had a really bad lapse in the second set," said Raonic. "But after that, happy with the way I closed it out."
Raonic won Thursday's opening set on a break in the ninth game but couldn't maintain momentum as Berdych stormed back in the second.
The Canadian woke up in the third, breaking Berdych twice to claim his 33rd of the season against 13 defeats.
"I was standing a little bit far back so it was giving me a little bit more time," Raonic said of his success on serve. "He serves pretty hard, but he wasn't necessarily hitting his spots all the time."
Raonic, ranked 19th, now plays Switzerland's Stanislas Wawrinka, who beat Japan's Kei Nishikori 6-3, 6-3.
"He can hit hard off both sides, I'm going to have to try to make him serve well," said Raonic. "If I can dictate and put myself in a front running position, I think I will have my opportunities."
Canadian doubles top seed Daniel Nestor and Max Mirnyi of Belarus lost their opening match to the pickup team of Italy's Andrea Seppi and Serb Viktor Troicki 4-6, 6-4, 10-8.
The 39-year-old Nestor has won this event four times, the first coming with former partner Mark Knowles in 1995.