Steve Corica's charges had left the door open for Melbourne City to leapfrog them late in the season with five draws in their previous six matches.
But Louis Verstraete and Guillermo May scored in the 53rd and 89th minutes to send Auckland seven points clear with two games to go.
If Melbourne City (43 points) lose to Western Sydney (39) on Saturday night, it will seal the premiership for Auckland (50).
Even a City draw would effectively deliver the silverware because Auckland have a superior goal difference (+23 to City's +12).
"We'll go back and have dinner at the hotel, and we'll probably all watch it together on a big screen," Corica said.
"The first thing was obviously taking care of business with us, first and foremost, and now we're hoping for the Wanderers to beat Melbourne City."
The former Sydney FC boss added: "Don't think I would have ever said that - but that's happened."
Auckland play Perth at home next Sunday, then finish the home-and-away season on the road against Western United.
Arthur Diles' fifth-placed Victory (39 points) have their finals position under threat, given Adelaide (36) and Sydney (34) are within touching distance.
Victory travel to face Macarthur away on Friday, then host Newcastle on May 4.
Auckland scored when Callan Elliott burst down the right and crossed the ball for Frances de Vries.
De Vries slipped the ball back to Verstraete, and the Belgian midfielder's skidding shot from the edge of the area nestled in the bottom corner.
Mitch Langerak was adamant Logan Rogerson was obstructing his vision from an offside position, but Kasey Bos's back foot kept the Auckland attacker onside.
Six minutes later Auckland goalkeeper Alex Paulsen made a ridiculous save from close range to deny Velupillay, then Alex Badolato skimmed a shot over the bar in the 64th minute.
Paulsen brilliantly dived down low to scoop away a Nikos Vergos header in the 86th minute.
"There's moments in games. You don't know when they're going to come, but that was his moment. Fantastic save," Corica said.
Then, Verstraete pounced on a loose Roderick Miranda pass and squared the ball for May to tap home, sending a packed away bay into ecstasy.
"The first goal ... we don't get the line up in time, and otherwise he'd be offside," Diles said.
"(We were) 1-0 down and their keeper makes a world-class save.
"They're the moments. And in the end, they didn't go with us today."
Auckland's Chilean midfielder Luis Gallegos was forced off in the 44th minute through injury, with Corica unsure of its severity.
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