Duhamel, from Lively, Ont., and Radford, from Balmertown, Ont., won the pairs event Saturday at the NHK Trophy, their second victory of the season on figure skating's Grand Prix circuit.
The victory secured their spot in the Grand Prix Final, but came with a few mistakes, including a fall by Duhamel on their quad throw Salchow — a difficult element that virtually no other pairs teams are performing this season.
"We were happy to win today but it is not as fun when you don't skate your best," Duhamel said. "It's good for us to get the quad out there at every single competition because we want to be able to land it in the program consistently by the time we get to worlds."
The Canadians, who also won Skate Canada International in Kelowna, B.C., scored 127.08 points to finish ahead of world junior champions Xiaoyu Yu and Yang Jin of China (121.85). Yuko Kavaguti and Alexander Smirnov of Russia were third with 199 points.
"The long program was a lot more challenging for us today after a great short program (Friday)," Radford said. "We were expecting more of ourselves but we understand it is still relatively early in the season and we don't want to peak right now. But we know it's going to take a lot more than we had today to be on top of the podium in Barcelona (Grand Prix Final) and ultimately at the world championships."
Kaitlyn Weaver and Andrew Poje of Waterloo, Ont., head into Sunday's free dance program in first place. The Canadians scored 67.51 in the short program, ahead of Britain's Penny Coomes and Nicholas Buckland (60.49). Ksenia Monko and Kirill Khaliavin of Russia were third (59.70).
"It was a great program for us today," Weaver said. "There were a couple of level issues but we felt it was much stronger than at Skate Canada. Now we just want to build on that momentum for the free dance."
Japanese skater Yuzuru Hanyu finished fourth, a result that allowed the Olympic champion to qualify for next month's Grand Prix Final by a slim margin.
Hanyu, who was fifth after the short program, doubled his opening quad Salchow and fell on the quad toe loop but finished with 229.80 points. Daisuke Murakami of Japan won with 246.07 points followed by Sergei Voronov of Russia with 236.65. Takahito Mura of Japan, who was first after the short program, placed third with 234.44 points.
Elladj Balde of Pierrefonds, Que., climbed from seventh to sixth. Jeremy Ten of Vancouver finished eighth.
Baldje, who suffered a concussion last month that kept him off the ice for three weeks, skated a clean program including a quad toe loop and triple Axel.
"Considering the situation that I had only two weeks of full training I did a really satisfying job," Baldje said.
Ten landed his first quad in competition Saturday.
"I really patted myself on the back for getting credit for that quad," Ten said. "Right now I feel I'm in control of my emotions and my nerves and it shows in how much I've improved this season."
Tatsuki Machida of Japan, Maxim Kovtun of Russia and Javier Fernandez of Spain had already qualified for the GP Finals in Barcelona and will be joined by Hanyu, Voronov and Mura.
Hanyu finished just fifteen-hundredths of a point ahead of Jeremy Abbott of the United States, who was fifth with 229.65. His nine points for finishing fourth were enough to put him in the GP Final combined with the 13 points he earned at the Cup of China three weeks ago where he was injured in a scary collision with Yan Han in warm-ups, but competed to place second.
Hanyu, who was diagnosed with bruising to his head and chin after collision in Shanghai, wasn't sure if he could take part in the NHK until Wednesday but decided to go ahead as he felt better in practice and needed the points to reach the final.
"I feel I made the right decision to compete," said Hanyu, who trains in Toronto with Brian Orser. "I wasn't in the best shape physically or mentally, but am proud that I was able to take part in the two events after all that happened."
Gracie Gold of the United States won the women's free skate to finish first overall and wrap up a place at the GP Final.
Gold, first after the short program, finished the free skate with 191.16 points, ahead of Alena Leonova of Russia, who received 186.40 points. Satoko Miyahara of Japan was third with 179.02.
The U.S. champion only had four triple jumps in her routine to Phantom of the Opera but scored high marks for her spins and step sequences en route to winning her first senior Grand Prix title.
"I'm very happy to win my first GP and senior international," Gold said. "But I know I can do better and improve on this performance."
She will join compatriot Ashley Wagner and Russians Elena Radionova, Elizaveta Tuktamysheva, Anna Pogorilaya and Julia Lipnitskaia at the GP Final in Barcelona next month.
— With files from The Associated Press.