Emery made 43 saves, including a point blank stop on Mikael Samuelsson with 2:39 remaining, and Ottawa scored three goals in a 5:01 span of the second period Tuesday night to beat Detroit 3-2.
The Senators, who broke a three-game losing streak, got two goals from Jason Spezza and another from Chris Neil.
But in Hasek's first game against the team he played for last year, it was the Senators' goalie who stood out.
"He was the dominant player, there's no question," said Ottawa coach Bryan Murray. "You talk about matchups, and all the headlines today Ray stepped up to the play and played outstanding."
Hasek, who made 19 saves, didn't play again for the Senators after injuring his groin in the Olympics. Ottawa wasn't happy that Hasek didn't return for the playoffs, and did not re-sign him. The veteran then signed a one-year free agent contract with the Red Wings.
He and Emery became good friends in 2005-06, when Emery was Hasek's backup.
"It's a special game playing against Dom, because of the legendary goalie he is and a being buddy of mine," Emery said. He's "a guy I've learned a lot off of. It was special to play him."
The game also meant a lot to Hasek.
"It was emotional," he said. "I was very disappointed."
All five goals came in the second period, after a scoreless first in which Detroit outshot Ottawa 18-3.
Spezza opened the scoring 1:44 into the middle period, when he intercepted Lang's cross-ice pass at the Ottawa blue line, went in on Hasek for a breakaway and beat him with a move and backhand shot.
"I've taken a million breakaways on him," Spezza said. "He was probably guessing as well and I won. What I wanted to do was make Dom make the first move."
Hasek made that first move because he made an incorrect guess.
"I just made a wrong decision. I thought he didn't have control of the puck and tried to pokecheck it," he said. "He made one more move. I have to admit, I made a mistake."
Neil made it 2-0 with a power-play goal at 5:19, when he tipped Christoph Schubert's shot from the point out of mid air for his ninth goal.
Spezza's second goal, his 17th, also came on the power play. He picked up the puck at the Detroit blue line and skated through all four Red Wings on the ice, beating Hasek with a forehand shot.
"I just think me and somebody else made some mistakes and they scored three goals," said Hasek. "Even though we outplayed them for 60 minutes."
Lang atoned for his giveaway just 25 seconds later when he beat Emery on a one-timer from the right face-off dot for his eighth goal. Datsyuk closed the gap to 3-2 with a power-play tally with 2:26 left in the second period. He also scored on a one-timer from the right face-off dot.
Emery's best save came on Datsyuk with about four minutes remaining in the second period.
With Emery down, Datsyuk appeared to have a wide open net as he got off a shot during a goal-mouth scramble. But Emery stretched out his glove hand for a spectacular save.
"He made a lot of saves, a couple of huge ones," said Red Wings' coach Mike Babcock. "The one on Pavel and the one on Sammy [Samuelsson]."