Tranmere will face Manchester United in the FA Cup Fourth Round after stunning Premier League Watford in extra time at Prenton Park.

Manny Monthe gave Rovers a first half lead before the Hornets drew level after the break through Kaylen Hinds, but substitute Paul Mullin headed home the winner in extra time, as the Whites served up what was their best performance of the season by a country mile.

Micky Mellon made just one change from the side that lost at home to Ipswich Town on Saturday, bringing in Corey Blackett-Taylor for the cup-tied Alex Woodyard.

The visitors took some time to adjust to the Rovers' less-than-perfect pitch, but when Joao Pedro burst through the middle on the break in the 10th minute his shot was block by the significant frame of Manny Monthe.

Wirral Globe: Manny Monthe celebrates putting Tranmere ahead against WatfordManny Monthe celebrates putting Tranmere ahead against Watford

Having enjoyed decent possession, Rovers first real opportunity arrived in the 22nd minute, when Blackett-Taylor skipped past his marker into the box and blasted a bobbling ball just over the bar.

Neil Danns then tried his luck with an ambitious half-volley from the edge of the box that faded wide, but it was Tranmere who were making all the running in the early stages.

Just before the half hour mark they should have led when a left-footed cross from Liam Ridehalgh reached Kieron Morris at the far post. His shot was saved, but with the goal at his mercy, Blackett-Taylor shanked the rebound over the bar. An opportunity missed.

Thankfully they didn't have to wait much longer to get a return on their superb efforts.

When Monthe rose highest to win a corner, Watford failed to clear their lines before the ball returned to the giant defender on the edge of the box.

His drilled effort took a slight deflection before crashing off the post and into the net, sending Prenton Park wild.

The shell-shocked southerners tried to respond immediately through Joseph Hungbo, but he could only fire his long-range strike over Scott Davies' bar.

The Rovers goalkeeper was a virtual spectator in the first half, as Tranmere continued to force their Premier League opponents further and further back, penning them into their own penalty area.

Blackett-Taylor continued to put the Hornet's defence in a spin, skipping past two before seeing his shot blocked for a corner by Christian Kabasele just before the break.

Nigel Pearson made a change at half time, bringing on Kayden Hinds for Tom Dele-Bashiru as he looked to find a way to get the visitors back into the match.

Wirral Globe: Connor Jennings on the attack against Watford in the FA Cup Third Round. Photo: Tony CoombesConnor Jennings on the attack against Watford in the FA Cup Third Round. Photo: Tony Coombes

When Pedro held off Peter Clarke, it looked like they would equalise quickly but Davies sprung into action, making a tremendous reflex save.

Watford went close again when Davies palmed away a corner that worked its way back to Holebas and his first time strike hit the outside of the post.

Mellon withdrew the excellent – but tiring – Ferrier for Mullin with 25 minutes remaining and the substitute wasted no time getting in on the action, squirming past two defenders before running into the clutches of goalkeeper Daniel Bachmann.

But on 68 minutes, Watford drew level when Davies couldn’t hold a header from Hinds and after a goalmouth scramble the ball came back to the Hornets substitute, who squeezed the ball home.

Mullin had a golden opportunity to put Tranmere immediately back in front when he knicked the ball past Bachmann, but with the ball running wide to an acute angle he could only hit the outside of the post.

As the game shifted into the final 10 minutes it was the League One side asking all the questions and they were very nearly answered.

As the game approached the 90 the magnificent midfield veteran Danns wriggled his way into the box and shot just wide.

But in the dying seconds of stoppage time he went closer still, selling his marker before pulling another effort wide in front of a gasping Kop end.

All square after 90 minutes and into extra time.

Watford fired the first shot from their rusty barrel with Callum Whelan pulling a full stretch out of Davies.

Wirral Globe: Tranmere players celebrate Paul Mullin's extra time winner against WatfordTranmere players celebrate Paul Mullin's extra time winner against Watford

But Tranmere were not to be denied and in the 104th minute of the contest they sensational retook the lead.

Exerting pressure on the visitors once again, substitute Harvey Gilmour crossed from the left before Blackett-Taylor’s flick on was head home by Mullin from close range, igniting a deafening roar across Birkenhead.

With momentum, Rovers came again and almost extended their lead, as Morris fired just wide from the edge of the box.

Mellon brought on Callum Woods for Blackett-Taylor at the start of the second period of extra time, as he tried to prevent Watford from overloading the flanks.

There were tired legs all over the pitch, but backed by a partisan crowd, Tranmere saw the game out to record one of the most stunning victories in their recent history.

Match Stats

Tranmere Rovers 2

Monthe 35, Mullin 104

Watford 1

Hinds 68

Half time: 1-0

Referee: Tony Harrington

Attendance: 10,039

Star man: Neil Danns (Tranmere midfielder)

Match rating: 5/5

Tranmere team (4-4-1-1): Davies, Caprice, Clarke, Monthe, Ridehalgh, Morris, Perkins, Danns (Gilmour 100), Blackett-Taylor (Woods 110), Jennings, Ferrier (Mullin 65 (Payne 116))

Tranmere subs: Pilling, Nelson, Hepburn-Murphy

Watford team (4-3-3): Bachmann, Holebas, Kabasele, Barrett, Spencer-Adams, Quina (Wise 106), Dele-Bashiru (Hinds 46), Pedro (Dalby 81), Gray, Whelan, Hungbo (Bennetts 99)

Watford subs: Dahlberg, Balogun, Janjeva