In the tight and intimidating surroundings in Zenica, the hosts had the first chance when Erdin Demirović’s shot from the edge of the box was held by Gianluigi Donnarumma.
However, his opposite number Nikola Vasilj had a disastrous moment after a quarter of an hour when he gifted the ball straight to Nicolò Barella just outside of the box.
The Inter midfielder squared to Moise Kean and he finished superbly, curling home first-time with his instep to give the Azzurri the lead.
To Bosnia’s credit, they did not wilt and came right back at their opponents. First, Ivan Bašić stung the palms of Donnarumma from outside the box before Nikola Katić should have done better with a free header.
The pressure continued as Demirović glanced a header wide from a free-kick.
Already under the cosh despite their advantage, Genaro Gattuso’s side were dealt a further blow just before the break when Alessandro Bastoni was shown a straight red card for unceremoniously hacking down Amar Memić as he streaked away from the Italian defence.
In a bid to kick on with their man advantage, Sergej Barbarez made a double sub at the break and one of them – Kerim Alajbegović – was the next to test Donnarumma.
But despite their rearguard creaking, Italy almost had a chance to open up their advantage against the run of play on the hour when Bosnia were sloppy in possession again in the middle of the park and Kean went surging towards goal.
However, the Fiorentina forward couldn’t keep his nerve and blazed over when one-on-one with Vasilj.
If this game were a boxing match, Bosnia would have been ahead on points, and on 70 minutes, Donnarumma was forced into arguably his best save of the night, albeit there were a few to choose from.
The Manchester City stopper got down low to his right to tip Benjamin Tahirović’s effort around the post as his side continued to bend but not break.
However, after making another good stop from an Edin Džeko header, there was nothing Italy’s number one could do as Haris Tabaković forced the ball over the line for a deserved albeit ugly equaliser with just over 10 minutes remaining.
This meant that it would take at least another 30 minutes to decide these sides’ World Cup fate, and the first half of ET was a cagey affair – but not without controversy.
Marco Palestra was sent away behind the Bosnian defence and was brought down just outside the box by Tarek Muharemović, and, while Italy were screaming for a red like Bastoni, referee Clément Turpin brandished a yellow.
After the free-kick was recycled out right, Palestra picked out Sebastiano Esposito at the back post but he was denied well by Vasilj.
The best chance of the second half of ET came when Tahirović fizzed a low shot wide, meaning that a shoot-out would decide who would be going to North America this summer and who would be watching at home.
The partisan atmosphere inside the Bilini Polje Stadium clearly got to Esposito, who missed Italy’s first kick, and with Bosnia having scored their first three spot kicks with aplomb, Bryan Cristante rattled the crossbar.
That meant that Esmir Bajraktarević’s effort that squeezed under Donnarumma sent his nation back to the World Cup amid jubilant scenes from almost all corners of the ground.
Flashscore Man of the Match: Haris Tabaković (Bosnia & Herzegovina)