Tampa Bay coach Jon Cooper said the Lightning's recent success has come from eliminating the risk elements from their game.
"You look at some of the games we won early in the season, it was only one, but it was just too much risk and we were feeding other teams’ rushes and feeding them chances," Cooper said. "As you can see, we've changed the way we've played and changed our mentality and the losses have turned into wins."
Adam Erne scored for Dallas (6-3-2), which has a five-game point streak (3-0-2). Oettinger made 30 saves.
"We had our chances, you know, a 5-on-3 to get something out of it but we didn't," Stars coach Glen Gulutzan said. "We've talked at length about just trying to muck out points and grind out points and put ourselves in position to get two. We would've loved to get two tonight. It was tight that way, but we wanted two."
Hagel gave the Lightning a 1-0 lead with a power-play goal at 15:02 of the second period when he slid the puck over the goal line off a follow-up of a shot from Gage Goncalves. The goal was initially waved off, but video review initiated by the NHL Situation Room showed the puck crossed the goal line.
"We're just playing fast right now," Hagel said. "The D are doing an incredible job of getting the puck up the ice and letting the forwards keep their speed. Our D has been doing an incredible job. These 2-1 games you learn a lot about yourself and it's a good time to learn about yourself, especially early in the season."