World champions Meryl Davis and Charlie White of the United States won the gold medal with 186.65 points well ahead of runners-up Anna Cappellini and Luca Lanotte of Italy with 160.06. Maia Shibutani and Alex Shibutani of the U.S. were third at 157.58.
Poirier, a 2010 Olympian from Unionville, Ont., was out three months after sustaining a serious leg injury this past spring. His leg didn't seem to be a factor as the couple delivered a clean program packed with original moves that received an ovation from the Japanese crowd.
"We were very solid and that was important for us heading into nationals," said Poirier, who joined forces with Gilles in 2011. "Our training has been so limited over the last month. Starting in Japan was good for us because we always enjoy competing for us and they have a great crowd. We're confident we are on our way to getting even better."
Gilles said the couple had a slight fear of the unknown heading into the event.
"The last couple of weeks been a bit of a roller coaster for us," said the Toronto resident. "To lay down two solid programs was a bit emotional. It is something we will always remember."
Gilles and Poirier were one of two Canadian entries at the competition. On Saturday, Paige Lawrence of Kennedy, Sask., and Rudi Swiegers of Kipling, Sask., were sixth in pairs.