Defending Tokyo champion Nadal will face Santiago Giraldo next after the Colombian beat Russia's Dmitry Tursunov 6-4, 7-6 to reach the last eight of the $1.34 million hard court event.
"It's not fun if you can't touch the ball," Nadal told reporters after dashing off to the practice court following his match. "His first two service games I didn't win a point.
"But it's fantastic mental practice to try to stay focused on your serve and to wait for your chances on the return. Today I didn't have one break point on my serve, which is a very positive thing." In the next match on Center Court, Britain's Andy Murray joined Nadal in the last eight by crushing American Alex Bogomolov 6-1, 6-2, relishing the warmer conditions a day after playing under a closed roof.
Nadal took a tight first set when Raonic's biggest weapon let him down, the 20-year-old double-faulting before slicing a volley long on an aggressive charge to the net.
Raonic, making his return to the men's tour after hip surgery following Wimbledon, appeared sapped of strength in the second set as the afternoon shadows crept across center court.
With Nadal pulling the strings in almost every rally, Raonic gifted the Spaniard a break for 4-2 with a shanked forehand which flew into the crowd.
Nadal, playing his first tournament since helping Spain reach the Davis Cup final last month, quickly moved in for the kill, ripping a forehand into the corner to finish the job.
"The match was difficult but not very hard physically," the 10-times grand slam tournament champion said.
"He had a lot of free points on his serve so I was still felt fresh. I had a day off yesterday so we decided I could get some practice." Nadal's Spanish teammate David Ferrer made hard work of reaching the last eight, the third seed grinding out a 4-6, 6-2, 6-2 win over Australian qualifier Matthew Ebden.
Ferrer, Japan Open winner in 2007, will play seventh seed Radek Stepanek of the Czech Republic next.
Second seed Murray, fresh off winning his third title of the year in Bangkok at the weekend, needed just 60 minutes to brush aside Bogomolov with a clinical performance.
Murray will play the winner of Thursday's late match between Argentine David Nalbandian and Ivan Dodig of Croatia in the quarterfinals.
In Beijing, top-seeded players Jo-Wilfried Tsonga and Caroline Wozniacki both advanced to the quarterfinals at the China Open on Thursday.
Tsonga beat Chinese qualifier Zheng Ze 6-3, 6-4 and Wozniacki defeated Kaia Kanepi of Estonia 6-3, 7-6 (3).
"It was not easy today, and I'm happy to win, of course, even if I was supposed to win," Tsonga said.
The Frenchman, who won a tournament at home in Metz last month, is competing for one of the four remaining spots at the season-ending ATP World Tour Finals in London.
In the next round, he will face Juan Carlos Ferrero of Spain, who beat Marcel Granollers 6-4, 6-4.
"I think he's a great player," Ferrero said of Tsonga. "He's in a good shape. He's been playing very good tennis most of the season on the hard courts, and of course he's one of the favorites to win the tournament." Also in Friday's quarterfinals, Tomas Berdych of the Czech Republic will face Fernando Verdasco of Spain, Ivan Ljubicic of Croatia will meet Mikhail Youzhny of Russia, and Kevin Anderson of South Africa will play Marin Cilic of Croatia.
In the women's tournament, Wozniacki rebounded from last week's loss to Kanepi at the Pan Pacific Open in Tokyo.
"I knew it was going to be a tough match," the top-ranked Dane said. "I'm really happy to get this win and get my revenge." Wozniacki will next face Flavia Pennetta of Italy, who defeated Dominika Cibulkova of Slovakia 6-1, 4-6, 6-4.
Also, second-seeded Victoria Azarenka pulled out of the tournament because of a right foot injury, giving 13th-seeded Anastasia Pavlyuchenkova of Russia a walkover win.
Azarenka, who lost in doubles on Wednesday, said her foot has been bothering her since Tokyo.
"I'm not sure about recovery time but I will consult my doctor," the fourth-ranked Azarenka said.
In other quarterfinal matches, Pavlyuchenkova will face Andrea Petkovic of Germany and Monica Niculescu of Romania will take on Maria Kirilenko of Russia.
