Raonic, who became the first Canadian men's singles player to make the ATP top-10 after the tour released its new rankings Monday, lost Sunday's final in Montreal to Rafael Nadal.
The Thornhill, Ont., product moved up three spots to No. 10, which had been his previous career high, after becoming the first Canadian to play for the title of the country's top tournament in more than 50 years.
Raonic headed straight for the Cincinnati event after the defeat in Montreal and hit the practise court.
He also said he could have dealt with the fair-play situation better.
"I made a mistake in the spur of the moment, I guess because I hadn't been faced with it before," Raonic said. "I'm disappointed with myself how I dealt with it, and it's something I learned a lot from."
Raonic was given what amounted to a pass late in the match when his left foot touched the net at the end of a shot, which is in violation of the rules. The chair umpire was following the trajectory of the ball — a Raonic winner — and failed to notice the infraction. Raonic took the point and the eventual win into the quarter-finals.
While Del Potro was steaming on Twitter, Raonic had other things on his plate as he reached the historic final.
"I didn't have the opportunity until really the last two days to think about it that much. It's something that I feel sorry about and something I want to apologize to Juan when I see him here," said the 22-year-old. "I don't think I dealt with that the right way.
"It's something that probably in the future I should call on myself."
The 12th seed at the Cincinnati tournament, Raonic will start his campaign at the last major tune-up prior to the start of the U.S. Open with a match against American wild card Jack Sock on Tuesday. There will some revenge involved after Sock bounced Raonic out in the first round at Memphis in February, three days after he lifted the San Jose title for a third year in a row.
Raonic also praised his new coaching situation Monday, characterizing his spring choice of Ivan Ljubicic as "a decision that took a lot of thought and a lot of discussion."
"It was about making sure that we see eye to eye on what I need to do and to compete with the best guys and what I need to do to get better and to be able to achieve my goals," he said. "We did see eye-to-eye in trying to find a way to be more aggressive playing, find more opportunities to go forward, and focus a lot on development and knowing that this was the most important thing for me to achieve what I want to achieve in tennis.
"Knowing how particularly smart he was on court at finding solutions and how he saw the game really well, this gave me a lot of confidence that he would be able to translate and sort of pass on his advice to me."
Despite his move into the top-10, Raonic didn't have the biggest jump in the rankings among Canadian men.
Vasek Pospisil of Vernon, B.C., who lost to Raonic in the Rogers Cup semifinals, rose 31 spots to No. 40 to reach his career high.
Nadal moved up one spot to No. 3 after winning the Rogers Cup.