Roared on by a fervent home crowd inside St James’ Park, Newcastle came flying out of the blocks in the opening quarter-hour, with Sandro Tonali and Anthony Elanga seeing a pair of efforts unconvincingly saved by Joan Garcia.
Grateful to have survived that frenzied start, Barcelona grew into the contest, and they nearly took a fortuitous lead when Dan Burn deflected Fermin Lopez’s delivery inches wide of his own goal.
Determined to avoid a repeat of their matchday one defeat to the Blaugrana in the league phase, Newcastle continued to apply pressure as the first half progressed.
However, Eddie Howe’s men were unable to find the all-important finishing touch in the final third, as a wicked cross from Elanga narrowly evaded William Osula at the back post.
Having more than held their own in a closely-fought opening period, the Magpies remained on the front foot at the start of the second half, with Osula firing wastefully over from Lewis Hall’s well-timed through ball. Barca looked to threaten themselves at the other end, but Raphinha’s low cross was uncharacteristically swept wide by Robert Lewandowski.
With nothing to separate the two sides heading into the final 25 minutes, both managers turned to their respective benches in the hope of injecting fresh impetus into the contest. Jacob Murphy nearly delivered within minutes of his introduction, only for the winger to volley horribly over from 12 yards.
Undeterred, Newcastle went even closer to a breakthrough in the 74th minute when Harvey Barnes curled agonisingly against the post from inside the box, before Joelinton’s subsequent rebound was correctly ruled out for offside.
However, there was no denying the hosts with four minutes remaining, with Barnes finding himself free in the box to coolly volley home from Murphy’s inch-perfect delivery, sending the Gallowgate End into raptures.
The Magpies’ joy was ultimately short-lived, though, as in the final minute of stoppage time, Malick Thiaw clumsily tripped Dani Olmo in the box, allowing Yamal to step up and confidently convert from the spot to shatter Toon hearts at the death.
It was a gut-wrenching end for Howe’s side, who must now pick themselves up as they travel to Catalonia next week with the tie fascinatingly poised.
Flashscore Man of the Match: Harvey Barnes (Newcastle United)