Niklas Hagman's shot went wide of the net and the puck pinballed off the end boards and onto the stick of Halpern to the left of the Nashville goal. Halpern popped his third goal of the season into an open net vacated when Predators goaltender Tomas Vokoun tried to play the puck behind the net.
Stars rookie Mike Smith stopped 17 shots for his second shutout in his fourth career start, improving his record to 4-1.
Smith was the goalie of record on Monday night, coming on in relief of regular starter Marty Turco in the first period; Turco gave up two goals on the first five shots then, but the Stars rallied behind Smith for a 5-4 victory over Colorado.
Smith also had a little luck on his side when David Legwand of Nashville saw a shot ring off the right goalpost with about 10 minutes left.
Vokoun made 25 saves for the Predators, who had been riding a 4-0-1 streak over their previous five games. Vokoun made a big stop on Dallas' Mike Ribeiro from close range with 1:56 left to deny the Stars' bid for a second goal.
The Stars are 8-1-1 against the Predators in their last 10 meetings.
Dallas' Mike Modano was awarded a penalty shot at 6:40 of the first period, but Modano's shot from about 20 feet hit the right goalpost. Modano had gone in on a short-handed breakaway and was held by Nashville captain Kimmo Timonen, resulting in the penalty shot.
Both goalies were perfect over the opening 40 minutes, with Dallas holding a 16-14 shots-on-goal edge heading into the final period.
The Predators were without former Stars center Jason Arnott, who sustained a right knee injury earlier this week and will miss three to six weeks after arthroscopic surgery.
Notes:The Stars are 4-2 in their last six games. ... Dallas RW Jere Lehtinen missed his fourth straight game due to a leg injury. ... Stars captain Brenden Morrow is also out with a groin injury. Morrow was hurt Monday night and was sitting out his first game. ... Nashville RW J.P. Dumont was helped to the locker room early in the second period after twisting his knee during a scrum in front of the Dallas net, but was back on the ice late in the period. ... Modano is 0-for-4 for his career on penalty shots.