Joffrey Lupul scored the only goal in the 3.
Gustavsson made 26 saves in Toronto's second straight win, while the Stars got 20 saves from Lehtonen in having their two-game win streak snapped.
Neither team capitalized on a power play in the final four minutes of regulation, and there were only two shots -- both by Toronto -- in the added time.
Nystrom made a nice forehand to backhand move to get between two defenders and wristed a shot up high for the game's first goal at 4:03 of the opening frame.
Midway through the first, Crabb tied it on a nifty re-direct between his legs on a shot from Phaneuf, whose one-timer with 5:07 remaining trickled past Lehtonen and over the goal line for a power-play goal.
Nystrom was on the receiving end of a terrific Dvorak pass at 4:38 of the second to knot the game again.
Dallas went 0-for-4 on the power play and has gone scoreless in its last 16 chances with the man advantage...This was the Leafs' first win in Dallas since October 22, 2003, though they had only made two other trips since.