Jimmy Howard took a shutout deep into the third period before surrendering a goal to Zemgus Girgensons, but the Sabres could not deliver the equalizer.
Samuelsson tipped in a shot by Cory Emmerton with 7:55 to go in the first and Datsyuk quickly added a backhander that escaped Ryan Miller.
Howard had to make only 19 saves as he began his eighth season with the Red Wings. His 2012-13 season came to a disappointing end when he allowed 10 goals over the final three games of Detroit's loss in the conference semifinals to eventual Stanley Cup champion Chicago.
Detroit took a 3-1 lead in that series before the Blackhawks put together their rally.
Miller stopped 32 shots in taking the loss.