The 23rd-seed crushed Italian Filippo Volandri 6-4, 6-0, 6-2 at the Australian Open on Tuesday and joined fellow Canadians Aleksandra Wozniak and Stephanie Dubois in the second round.
Raonic, from Thornhill, Ont., withdrew from the Kooyong Classic last week after playing one match at the warmup event in Melbourne, saying he felt fatigued after travelling from India, where he claimed his second career title at the Chennai Open.
"I'm fine after last week," said Raonic, who attributed his illness to a lack of sleep in the three nights following his Chennai title. "I slept maybe a total of six hours.
"It just got too heavy on me. But today was good. I got through it even if not everything in my game was working perfectly. I got the job done."
Raonic needed just 91 minutes for his victory, completed with 13 aces and the same number of winners against a player ranked 47 spots below him on the ATP list. Raonic is ranked 25th in the world.
Temperatures in Melbourne reached the mid-30s, but Raonic said he was bothered more by wind than heat.
"The wind was not constant, it was more gusting. It was coming from all different ways," he said.
"I was trying to impose my game in all of that but later I got more patient. I wasn't serving the best today."
Raonic next plays Philipp Petzschner, a winner over Czech Lukas Rosol 6-0, 6-0, 6-2. Raonic beat the German last autumn indoors in Stockholm after losing to him on grass at Halle, Germany.
"He goes for shots and can play well," Raonic said of Petzschner. "It's about focusing on what I have to do and impose on him, He can do a lot of things well.
"If he gets a head start he can dictate. I'll try to put myself ahead, not necessarily in the score but dictating play. If I can do that I give myself a good chance."
Wozniak marked her first success in Melbourne as she defeated China's Zhang Shuai 6-3, 6-3 to earn her first career Australian Open victory.
Dubois of Laval, Que., defeated Russian Elena Vesnina 6-4, 1-6, 6-4 to join Wozniak in the second round.
Wozniak, from Blainville, Que., will next play Russian Maria Kirilenko, a 6-4, 6-2 winner over Australian Jarmila Gajdosova.
Vancouver's Rebecca Marino fell 6-4, 6-2 to Hungary's Greta Arn.
"I knew I had to start fast, it was windy and the conditions were difficult, it was coming in and going out," said Wozniak. "And it got hotter the longer we played.
"It was 36 Celsius today, so I wanted to get off court as soon as possible."
Wozniak has been troubled over the past year by a forearm injury which dropped her to No. 102 in the WTA's rankings. The 24-year-old is competing in Melbourne for the first time since 2010, when she lost in the first round. She also lost opening matches in 2009 and 2007 at Melbourne Park.
"Last year I missed it here because I was still struggling with my forearm injury," said Wozniak. "I'm happy to be here this year and win my first match."
Wozniak came out firing against wild card Zhang — ranked No. 127 in the world. The Canadian got out to a 4-0 lead but struggled to close out the first set.
Wozniak missed on two set points before losing one of her breaks, but finished the set on her fourth chance with a winner after 39 minutes.
The second set was more competitive, but Wozniak broke for 5-3 and served out the victory a game later as Zhang returned long.