The third-seeded Canadian downed Japan's Go Soeda 6-4, 7-6 (0) on Wednesday in the first round of the Japan Open as he tries to finish the ATP Tour season on a high note.
Raonic, from Thornhill, Ont., finished with a forehand winner down the line as he completely overwhelmed his Japanese opponent in the tiebreaker.
"I did a lot of things well, I served well in tough situations even if my serve was going in and out a bit. It was an early match for me (11 a.m.)," said Raonic, who won the Thailand Open on Sunday. "Most of my matches in Bangkok were in late afternoon or at night.
"But I believe I have adjusted well. I've dealt with a lot of issues but in the important moments my game has held up. I served well and played a good tiebreaker, I buckled down when I had to."
Raonic will next play Jeremy Chardy of France, who defeated Swiss qualifier Marco Chiudinelli 7-6 (2), 3-6, 7-6 (6).
The 22-year-old Canadian is a provisional 11th in the race to the eight-man season wrapup in London next month and is working in Asia to try to qualify for the elite event for the first time.
Raonic improved to 38-17 on the season with the victory. Soeda is now 0-9 at his home tournament.
Raonic had 24 aces and never faced a break point. His break of Soeda in the third game of the opening set was enough to win the set after 35 minutes with his 10th ace. He dominated in the second-set tiebreaker to earn the victory.
Raonic took a break after Wimbledon and has been working on his conditioning in recent weeks. He's won 17 matches and lost five since his appearance at the All-England Club.
"I think taking a longer period after Wimbledon to work on fitness really helped me," said Raonic. "When I returned to the court I had more confidence and I've kept that going. It's still helping me a lot at this moment."
Raonic is playing Tokyo for the fourth straight year, standing 7-3 in the Japanese capital after making his breakthrough as a qualifier in only his second ATP-level event.
Also Wednesday, top-seeded Juan Martin del Potro moved into the quarter-finals with a comfortable 6-2, 6-2 win over fellow Argentine Carlos Berlocq.
Del Potro broke Berlocq's serve twice in the second set, and lost only eight points on serve under the roof, closed by rain. After Tuesday's three-set victory over Marcos Baghdatis, del Potro said it was good to find his rhythm.
"I played a lot better than yesterday," del Potro said. "I served well, my forehand was strong and I was able to break his serve and be aggressive. I had control of the match all the time which was important to me."
Del Potro, who is seeking his third title of the season following victories in Rotterdam and Washington, will next play Alexandr Dolgopolov of Ukraine, who defeated eighth-seeded Janko Tipsarevic of Serbia 6-3, 7-6 (2).
In the day's only upset, Ivan Dodig of Croatia ousted second-seeded Jo-Wilfried Tsonga 6-4, 7-6 (5).
Matching 2009 champion Tsonga with nine aces, Dodig saved all three break points he faced.
Dodig will attempt to earn a place in his third semifinal of 2013 against Jarkko Nieminen of Finalnd, who beat Michal Przysiezny of Poland 6-7 (4), 6-4, 6-2.
Raonic lost in the final last year to local favourite Kei Nishikori, who will face Feliciano Lopez of Spain in the second round on Thursday.
The fourth-seeded Nishikori is on the verge of becoming the first Japanese player to break into the top 10 and is bidding to win his second title of the season.
With files from The Associated Press.