Australia 556 for 9 dec (Khawaja 160, Carey 93, Ashraf 2-55) and 97 for 2 dec (Khawaja 44*, Labuschagne 44, Afridi 1-21) drew with Pakistan 148 (Babar 36, Starc 3-29) and 443 for 7 (Babar 196, Rizwan 104*, Lyon 4-112)
Babar Azam thwarted Australia with an extraordinary 196 as a gutsy Pakistan survived a dramatic late collapse to remarkably draw the second Test after batting through 171.4 overs to ensure the historic series remained deadlocked.
Against all the odds, Pakistan finished their marathon second innings at 443 for 7 with Mohammad Rizwan unbeaten on 104 and Nauman Ali on 0 off 18 balls. Pakistan fell short of a record run chase by 63 runs, but in getting through they achieved the second most overs survived in the fourth innings behind the timeless Test between South Africa and England in Durban in 1939.
Having endured a two-year century drought, Babar made up for lost time with his highest Test score and the highest fourth-innings score by a captain in Test history. Just as the match was petering out to a draw, there was a late twist in the final hour when Babar's 425-ball epic ended when he prodded to bat-pad offspinner Nathan Lyon.
Finally getting reward for his unwavering bowling, Lyon then picked up Faheem Ashraf on the next ball as Australia's spirits lifted ahead of the third new ball. He didn't claim a hat-trick but Lyon removed Sajid Khan shortly after and Australia suddenly needed just three wickets with eight overs left.
In a nerve-jangling passage, Australia had seven fielders around the bat for the bowling of Lyon and debutant Mitchell Swepson, who almost had the big wicket of Rizwan with 19 balls left only for Usman Khawaja to drop a low chance at extra cover.
It proved to be Australia's last chance with Rizwan notching his century in the penultimate over and then keeping Swepson at bay in the final over as Pakistan conjured the improbable.
A weary Australia were gutted for the fourth time in just over a year they failed to bowl out their opponent in the fourth innings. But Lyon, who endured criticism during those matches, produced a Herculean effort as did captain Pat Cummins.
Swepson, Australia's first specialist legspinner since Bryce McGain in 2009, was inconsistent but looked threatening at times in an encouraging debut.
But with their late rally falling short, it was a disappointment for Australia, who had dominated most of the match and declared both their innings in a Test in Asia for just the second time.
After routing Pakistan for just 148 off 53 overs in the first innings, Australia appeared on course for victory but they were denied by Babar, who produced an innings for the ages.
Babar came to the crease with Pakistan teetering at 21 for 2 just after lunch on day four as the hosts appeared to be headed for a crushing defeat in their fortress. But they incredibly lost just two wickets over the next 137 overs in shades of their batting dominance in Rawalpindi.
The backbone of Pakistan's defiance was Babar's 228-run partnership with opener Abdullah Shafique, who made 96, as the pair batted through almost three sessions. Babar also combined with Rizwan for a century partnership to ensure Pakistan held on for a famous draw.
With oppressive conditions in Karachi throughout the match, the pitch was marked by widening cracks in a contrast to the docile Rawalpindi deck amid a stale first Test draw. There was swing, sharp turn and variable bounce at times earlier in the match, but the pitch did not significantly deteriorate although occasionally played tricks late on day five.
After tea, with Babar and Rizwan well set, it appeared Pakistan would make a bold attempt at mowing down the record chase as they scored 20 runs off the first two overs.
But with the ball getting old and not coming onto the bat, Pakistan decided the gamble to go for broke was too risky, and they shut up shop before Lyon's heroics threatened to undo all their hard work.
Babar's most testing period was before tea when he was dropped on consecutive balls by Travis Head and Marnus Labuschagne fielding close to the wicket off Swepson, who rebounded with menacing sharp turn and bounce after wayward bowling in the morning session.
Cummins had earlier almost single-handedly reignited Australia's push for victory with two wickets during a brilliant spell either side of lunch.
Having given themselves almost two full days, Australia rued two chances on day four against Shafique, who was dropped on 20 by Steven Smith in a regulation chance at slip and almost run out only for Cameron Green's throw to miss from mid-on.
With contrasting draws to start the series, this historic contest comes down to the third Test and Pakistan will enter with the momentum after their heroic performance in a match that will surely be talked about for a long time to come.
