On a surface catered for spinners seamer Nathan Ellis was the star, returning 4-33 in his nine overs with some key wickets.
In the absence of Pat Cummins, Josh Hazlewood and Mitch Starc Ellis stepped up to lead the attack superbly.
With stand-in captain Josh Inglis and Cam Green both making half-centuries the makeshift Australian XI set Pakistan a challenging 232 to win.
The home side rarely looked like getting close as they were bowled out for 190 to give the tourists a 41-run victory.
Pakistan had won the opening game by five wickets at Rawalpindi, where left-arm spinner Arafat Minhas took 5-32 on his ODI debut, after which Pakistan's Kiwi coach Mike Hesson knocked back criticism of preparing spin-friendly wickets.
Expecting another slow, low turner Australia went in to the match with a trio of specialist spinners, Adam Zampa replacing fast bowler Billy Stanlake having recovered from the neck spasms which forced him to miss the first ODI.
But it was pacer Ellis who had made the early breakthrough with a pair of quick wickets, and who came back to take more when it mattered.
Meanwhile spinners Matt Short (3-36), Matt Kuhnemann (1-41), Zampa (1-30) and Tanveer Sangha (1-22) kept the pressure on, cramping the scoring and taking regular wickets.
Only Ghazi Ghori (37) put up much resistance in the top order, but as a baking-hot day cooled and the evening crowd arrived Shadab Khan and Arafat added a threatening 59 in 15.3 overs.
Inglis turned to Ellis who trapped Arafat (33) leg before. That left Shadab playing a lone hand and he was last out for a 77, neatly stumped by Inglis off a legside wide bowled by Tanveer.
Australia had been put in to bat and the vagaries of the surface were evident from the first ball as Alex Carey got a thick inside-edge onto his stumps attempting to cut a wide loosener from Shaheen Shah Afridi that lacked pace and bounce.
Inglis took six off the next two balls, clipping inswingers off his pads, but having been 14 off seven he slowed as spin was introduced.
At the other end Short (15 off 24) went to a soft return catch while Labuschagne, though a Pakistan Super League-winning captain last month, struggled, out for a 12-ball five as he attempted a big sweep.
Cam Green dug in with Inglis and they took the score from 3-51 to 102 before Inglis was bowled by a shooter for a 74-ball 51.
Matt Renshaw, having survived an lbw shout on umpires call on five, and a run-out chance when stranded by Green on 15, added 65 before Green (53 off 92) holed out attempting his third six.
Renshaw went on to make a fine run-a-ball 43, manipulating space expertly, while Oliver Peake showcased his potential with 31 off 32, including ten in two balls in the last over off Haris Rauf who was bowling in the high 140s kph.
"It was a pretty good total in the end," Inglis said. "It would have been nice for someone to go on and get a big score, but …. we thought anything over 200, we were right in the game.
"You can always call on Nello (Ellis) on those sort of pitches, his variations are outstanding, and when you've got on-pace at 145 and then your slow balls at just over 100k an hour, it's really tough."
The decider is also in Lahore, on Thursday night (AEST).
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