Substitute Matthew Dolan snatched a dramatic injury-time equaliser as League Two Newport kept their FA Cup dream alive with a 1-1 draw against Middlesbrough at the Riverside Stadium.
Daniel Ayala's 51st-minute header looked set to send Tony Pulis' men through to the fifth round as the visitors were guilty of missing a succession of late chances.
But the Exiles' persistence paid off in dramatic fashion as Boro failed to clear a Josh Sheehan cross and Dolan - who started his career at Middlesbrough - poked the equaliser past Darren Randolph.
It was everything Newport deserved after a bright performance which saw Padraig Amond come close in the first minute and Antoine Semenyo missed two glorious opportunities to pull level.
Evidently undaunted by the occasion, the visitors - who had seen off Premier League Leicester in the previous round - started well and Amond almost gave them a dream lead inside the first minute.
Aden Flint then headed over from a Lewis Wing free-kick as Boro settled, but Newport looked far from unnerved as Semenyo skied a good chance over the bar on the half-hour.
Wing came closest to breaking the first-half deadlock three minutes later, when his free-kick struck the Newport wall and his second effort clattered the top of visiting 'keeper Nick Townsend's bar.
Driving rain greeted the teams at the start of the second half but Boro's spirit was far from dampened, with Britt Assombalonga coming close before Ayala rose above the static Exiles defence to head Lewis' corner home.
Wing almost added a second in the 71st minute, drilling a low effort which was well saved by Townsend, who then produced another fine fingertip save to stop a deflected effort from George Saville.
But despite Boro's creeping domination, Newport would still miss two glorious chances before Dolan's heroics.
Semenyo flashed a free header inches wide from a Dan Butler cross and in the 85th minute and missed an even better chance as he volleyed over the bar, leaving Dolan to have the final say.