Brentford avoided becoming Newport’s latest cup victims as they won 3-0 on penalties after a 1-1 draw at Rodney Parade.
Adam Lewis hit a post with Newport’s first effort, before Nathan Wood and Bryn Morris both saw theirs saved by Bees debutant Ellery Balcombe, and Keane Lewis-Potter settled the contest in the Premier League side’s favour.
Mathias Jensen thought he had won it in the 88th minute but teenage substitute Kiban Rai headed home deep into stoppage time to take the tie to spot-kicks.
The Welsh side have earned shock wins over Leeds, Leicester, Middlesbrough, Swansea, Watford and Luton in the last five years but they were denied another scalp as Brentford avoided a repeat of last year’s shoot-out defeat to Gillingham.
Exiles boss Graham Coughlan made five changes from Saturday’s 3-1 home win over Sutton.
Jonny Maxted made his debut in goal, while Josh Seberry came into the back line, Matty Bondswell and James Waite were drafted into midfield and fit-again Omar Bogle started up front.
Brentford made nine changes, with Vitaly Janelt and goalscorer Kevin Schade the only survivors from their weekend draw against Crystal Palace.
Thomas Frank handed debuts to goalkeeper Balcombe, Ukrainian midfielder Yehor Yarmoliuk and teenage forward Michael Olakigbe.
The first opportunity arrived after 18 minutes as the visitors recycled a corner and Lewis-Potter’s header looped over Maxted, but Harry Charsley was in the right place to clear the danger from under his own crossbar.
Kristoffer Ajer then saw a side-footed effort from 25 yards comfortably saved by Maxted two minutes later, before Schade’s fierce drive from the edge of the area was deflected behind.
That was one of eight corners won by Brentford in the first half but, despite enjoying 76 per cent possession, they could not get the early goal.
The home side could have opened the scoring after 34 minutes when Aaron Wildig and Bogle linked up well down the left flank and the striker produced a clever cross to pick out Charsley, who placed his header just wide of Balcombe’s right-hand post.
The lively Olakigbe went closest in the opening stages of the second half with a fizzing effort just over the angle of post and bar.
But Frank had seen enough after an hour and he introduced experienced trio Bryan Mbeumo, Yoane Wissa and Jensen.
Mbeumo forced Maxted into a smart save almost immediately.
Jensen made the visitors’ pressure tell two minutes from the end of normal time as he tapped in from close range after Mbeumo’s cross was cut back across goal by Lewis-Potter.
But County refused to lie down and Rai’s added-time header ensured the tie went the distance.