The former Reds Designated Player hit an injury-time winner in Dallas' 1-0 home win over Vancouver Whitecaps and marked the occasion by lashing out at Mariner who traded him to Texas in July.
"I'll never forget the words of [current TFC manager] Paul Mariner saying that he wants to make sure he'll send me to a last-place team and let me burn in the heat," said de Guzman said.
The victory allowed FC Dallas to go within a point of the fifth-placed Whitecaps in the West and de Guzman was thrilled to contribute as Mariner's Toronto remain at the bottom of the East.
"It worked out for myself, getting the last laugh, the karma of things," he added. "Right now who's the last place team in the league and who's battling for the playoffs?"