Newcastle needed extra-time goals from Joselu and Ayoze Perez to see off Sky Bet Championship side Blackburn with a 4-2 win in their FA Cup third-round replay.
Newcastle opened up what appeared a comfortable lead as 21-year-old pair Sean Longstaff (1) and Callum Roberts (22) put them in full control with their first goals for the club, but it would not last.
As time wore on, Blackburn looked most likely to find a winner and Bradley Dack missed a sitter in the first half of extra time, but moments later Joselu put Newcastle back ahead from what looked like an offside position when he turned in the rebound from Fabian Schar’s long-range drive.
Perez then put the result beyond doubt within seconds of the restart, running from inside his own half to meet Matt Ritchie’s pass and score a superb effort from a tight angle in the Blackburn box, and set up a fourth-round home tie with Watford.
Longstaff gave Newcastle a dream start when his effort deflected off Amari’i Bell and wrong-footed David Raya with just 57 seconds on the clock as the visitors raced out of the blocks – and kept going.
They fully deserved the two-goal advantage which was handed to them by Roberts 22 minutes in, as the midfielder smashed home Josh Murphy’s low cross from eight yards out to mark his first start for the club with a debut goal.
Blackburn had aimed for the physical presence of Danny Graham from most attacks and from one long ball into him he handed the hosts a lifeline when he waited for Armstrong to overlap, fed the former Newcastle player and his smart finish beat Woodman to halve the deficit.
That goal galvanised Blackburn and Lenihan missed a good chance when he headed wide from a corner – but it would act as a warm-up effort, as from a near-identical position he buried the ball into the top corner from another delivery on the stroke of half-time.
Newcastle were forced into a substitution at the break with Ciaran Clark injured, but his replacement Jamal Lascelles lasted only 11 minutes before he too limped off.
Rafa Benitez’s side ended the game with Fabian Schar and Isaac Hayden also carrying knocks, but they held on to force an additional 30 minutes and even hit the post when Hayden nodded against the woodwork from a corner.
In extra-time Blackburn sub Joe Nuttall headed wide of the near post from a good position but Dack then missed the chance of the game when the ball was nodded back into his path by Craig Conway, allowing him to run through but plant his finish wide with the goal gaping.
Moments later Newcastle went back in front in controversial circumstances, with the linesman’s flag absent when Joselu pounced on Raya’s error after Schar’s speculative effort from distance, racing forward from what seemed to be an offside position to slot into the corner once the goalkeeper had palmed the initial effort back in front of him.
Any sense of injustice was short-lived as Newcastle doubled their advantage moments into the second half of extra time, when Ritchie spotted Perez’s run and played him in on the half-way line with Blackburn pushing up, and after avoiding the challenge of two home defenders he smashed in a fourth from a tight angle.
That would prove enough as the hosts finally ran out of steam, putting Newcastle in the fourth round for the third time in as many years.