League One strugglers Tranmere produced a sensational second-half display as they fought back from 3-0 down to earn a replay against 10-man Watford.
Goals from Tom Dele-Bashiru, Nathaniel Chalobah and Roberto Pereyra had given the Hornets a 3-0 first-half lead.
Connor Jennings headed home to reduce the deficit before Manny Monthe’s shot set up a thrilling finish.
Paul Mullin made it 3-3 from the spot after Mason Barrett was brought down by Corey Blackett-Taylor.
Watford played the last few minutes of the match with 10 men after Pereyra was shown a straight red card by referee Graham Scott for his foul on Kieron Morris.
Tranmere halt Watford revival
This was an unwelcome jolt for manager Nigel Pearson, who had guided his side to four wins in the past five matches after taking over in early December.
It seemed as if his gamble in making nine changes to his starting XI had paid off when two superb strikes from Dele-Bashiru and Chalobah, followed by Pereyra’s side-foot finish, earned his side a three-goal lead going into the break.
They dominated while Micky Mellon’s Tranmere, 21st in League One, had failed to test Daniel Bachmann’s goal once during that period. But the Hornets eased off in the second half and that allowed their opponents back into the game.
Jennings set them on their way when he nodded in, before defender Monthe swept home after an awful handling error by Watford’s Austrian keeper, who was making his debut three years after joining the club.
With three minutes of the match remaining Barrett attempted to race into the Watford area but was brought down by Blackett-Taylor. After a video assistant referee review, Scott pointed to the spot.
Former Everton and Liverpool player Mullin showed no signs of nerves as he blasted his spot-kick past the reach of Bachmann.