Sorry Ryan Reynolds, AFC Wrexham are no match for Sheffield United's box office Billy Sharp

Just as this thrill-a-minute sequel was set to go another 30 minutes - Wrexham’s owner Ryan Reynolds no doubt pacing his LA condo as his stream buffered in and out - United’s own box office star unholstered his sidearm and slid home the winning goal deep into stoppage time.

Their leading man on so many occasions, the 37-year-old upstaged Wrexham and their glamorous owners Reynolds and Rob McElhenney, ending 180 minutes of classic FA Cup drama to send the Blades into a fifth-round tie with Tottenham Hotspur.

Sander Berge added a third before Sharp continued shooting from the hip in his post-match interview with ITV.

"I think they've been disrespectful with a few things before the game, thinking they were already through,” blasted Sharp.

“I'm glad we've beat them. I wasn't happy with a few of their players and I was a bit frustrated at the end because I should have put the game to bed before I did.

"I wasn't happy with the way they've been as a club before the game, eyeing up Spurs. They've not even beat us.

“We're an honest set of lads and we want to go as far as we can in the competition.

"They thought we were going to roll over when they got back into it. I think the referee was helping them as well.. we didn't get a thing all night."

Sharp and the Blades were aggrieved at referee Leigh Doughty’s handling of the second half in particular, one in which he awarded Wrexham two penalties, the first very soft, and denied United a clear-cut one when Oliver Norwood’s shot struck an arm.

Throw in flares on the pitch, four goals in the second half here, six goals in the first tie at the Racecourse Ground, and this was quite the Cup tie, one that should have the FA regretting the decision to can sequels (replays) after this round.

Certainly there was enough in the second half alone here to fill an episode of Wrexham’s Netflix documentary.

The first half had passed without major incident, United threatening with neat build-up, but failing to break through until they cleared a Wrexham corner and broke quickly in the 29th minute.

Iliman Ndiaye poked the ball past Wrexham’s last man who was 10 yards inside United’s half, to send both himself and James McAtee clear through on goal.

With the whole of Bramall Lane holding its breath and the 4,800 Wrexham fans in the away end fearing the worst, McAtee sent his shot past Rob Lainton but wide of the post.

The longer the game went on, with the Blades missing a glut of chances, the more the Hollywood scriptwriters inked their quills in anticipation.

United needed a goal to puncture the growing narrative and got it five minutes into the second half.

Sharp tore down the left, whipped over a cross that when it was recycled found Osborn, whose inside pass was weighted perfectly for Anel Ahmedhodzic to rifle into the roof of the net.

It should have been two minutes later, the elegant Berge playing McAtee through on the inside right channel and this time the Man City loanee made the right decision, sliding the ball across to Sharp but Lainton made a fine save.

There was always going to be a plot twist and it came when Mullin turned Ahmedhodzic and theatrically went over. Contact, minimal as it was, happened outside the area but referee Doughty pointed to the spot and Mullin delighted the baying fans behind the goal by blasting the ball into the back of the net.

If that penalty was dubious, the second concession 12 minutes later wasn’t.

Oliver Norwood was brought on to calm Sheffield United as temperatures rose, but all he succeeded in doing was sliding in recklessly to bring down Mullin.

After the ferocity with which Mullin struck the first penalty there seemed only one winner, but Davies was equal to the second, beating it out with a strong right fist.

United had chances to win it as Wrexham settled for extra time, Sharp missing one and having one disallowed.

But he had the last laugh, benefitting from Max Cleworth’s failure to cut out a raking through ball before bearing down on goal and coolly slotting home past Lainton.

Berge’s third from a smart McAtee cut back finally killed off a Wrexham side far stronger on the field and in their following both in the terraces and in the boardroom than their National League status suggests.

Sheffield United: Davies; Ahmedhodzic (Lowe 78), Egan, Robinson; Basham, Coulibaly (Norwood 68), Berge, McAtee, Osborn; Sharp, Ndiaye. Unused substitutes: Foderingham, Clark, Arblaster, Brooks, Starbuck, Marsh.

Wrexham: Lainton; Forde, Lennon (O’Connor 74, Lee 82), Tozer, Cleworth, Mendy (McAlinden 60); Young, Jones, Cannon; Mullin (Bickerstaff 82), Dalby (Palmer 60). Unused substitutes:Hosannah, Butler, Watson, James.

Referee: L Doughty (Lancashire).