Brad Richards, who had three assists, set up the winner.
Marc Denis, looking to rebound from a disappointing season in which he went from being the Lightning's No. 1 goalie to not making the postseason roster, stopped 36 shots.
Gratton, who also had a black right eye with swelling, said he was struck by an accidental high stick. Gratton added that he was scheduled to have the eye examined and expected to know more about his playing status on Thursday.
Dallas was also without a number of regulars, including goalie Marty Turco, center Mike Modano and defenseman Sergei Zubov. Modano and Zubov could make their preseason debuts Thursday at home against Colorado.