"Did he get four tonight?" a stunned Boudreau asked reporters. "So him and (Jaromir) Jagr are leading the league in scoring? What the hell is this world coming to?"
Selanne, 42, is the NHL's oldest player, while the 40-year-old Jagr also had two goals and two assists as Dallas beat Phoenix on opening night.
Selanne was pleased to know that he and the pair are still able to compete despite their age.
"Way to go old boys," he quipped. "Most of the night's you feel it's a young guy's game.
"That's a surprise (we're leading the scoring). But I'm happy for Jagr. I played since probably 1986 against him with the junior national teams and I am very proud that he can play and be as good, because I am telling you, it's not easy."
Boudreau marvelled at the output of the 20-year veteran, who finished with two goals and two assists in only 15:08 minutes of ice time against the Canucks.
"He defies age on certain nights," Boudreau said. "A 42-year-old getting four points in an NHL game ... it's quite amazing."
At 42 years 200 days, Selanne became the first NHLer to record four points at that age in a game since Gordie Howe did so at 42 years 326 days in February 1971 against Buffalo.
On Saturday, the Finn scored in the dying stages of the second period with a wrist shot on the power play before adding another near the midway point of the third to round out the scoring.
Meanwhile, his two assists were the products of crafty moves on face-offs on the power play.
And in an ominous warning to the rest of the league, Selanne says he is still not 100 per cent.
"Physically, health wise, I feel great," he said. "But I know I need at least four or five games to get my legs back.
"To be honest I can't wait until I start feeling good because it is going to be way more fun than this."
Ducks captain Ryan Getzlaf was in awe of his tireless teammate.
"It was an off night he said. He said he didn't feel very good," Getzlaf said. "I said: 'If you can have an off night and have four points, that's pretty good.'"
Despite the big night, Selanne preferred to focus on the win.
"We were talking about a good start and we got the good start," he said. "So that's always good, a lot of positive things today."