Derby County increased the pressure on Jose Mourinho as Scott Carson denied Phil Jones to secure a shock 8-7 penalty shoot-out win over 10-man Manchester United after a dramatic 2-2 draw at Old Trafford in the EFL Cup.
Marouane Fellaini's stoppage-time equaliser gave United – who had Sergio Romero sent off – a second bite, but after 15 successful penalties between the two sides, Jones saw his feeble effort saved by Carson.
The hosts wasted little time before taking the lead in the regulation 90 minutes, as Juan Mata rounded off a lovely early move, but Derby looked capable of troubling United and deservedly levelled early in the second half through Liverpool loanee Harry Wilson's stunning free-kick.
Things got more difficult for United when Romero was dismissed for handball outside his area and Derby capitalised through Jack Marriott, but Fellaini forced a shootout with a last-gasp equaliser.
United were unable to bail themselves out again, however, as Derby scored all of their spot-kicks and edged through when Jones failed from 12 yards.
United went ahead after just three minutes, doing so in style.
Anthony Martial's pass across the edge of the area was backheeled to Jesse Lingard by Romelu Lukaku, and the England midfielder found Mata, who finished with aplomb.
Derby stepped things up after the break and Wilson – who had previously gone close to an equaliser – found the net brilliantly in the 59th minute, picking out the top-left corner with a 30-yard free kick.
The 21-year-old then played a role in Romero's sending off, as the goalkeeper handled when trying to prevent Wilson getting past him.
Derby thought they had won it five minutes from time when Marriott nodded in from close range, but Fellaini headed a deflected cross beyond Carson deep into stoppage time.
The quality in the shootout was high, with all of the first 15 penalties beating Lee Grant – Romero's replacement – and Carson, but the latter dived down to his left to foil Jones and book Derby's passage into round four.
1 - Sergio Romero is the first Manchester United player to receive a straight red card at Old Trafford in any competition since Eric Bailly did so back in May 2017 against Celta Vigo in the Europa League. Bath. pic.twitter.com/EfQ4wFhQJQ— OptaJoe (@OptaJoe) September 25, 2018
What it means: The apprentice defeats the master
Mourinho was facing his former player Lampard for the first time, and although United technically claimed a draw in 90 minutes, there was little doubt which was the better team at Old Trafford.
Even after going behind, Derby looked fearless, brave and full of ideas, attacking United whenever the opportunity came.
In the second half, Derby were even more effective, with Mourinho's pragmatic tactics seeing the hosts struggle before going direct for the equaliser. The second goal flattered United, who ultimately got what they deserved.
No answer to Wilson
Many Derby players enjoyed fine outings, but Wilson was the pick of the bunch. Although he started on the left, the midfielder popped up all over the place, with his movement causing United real problems. He threatened the hosts' goal a couple of times before his gorgeous free-kick and was then key in Romero's dismissal.
Romero leaves United in trouble
In what was his first competitive appearance for United since the final day of last season, Romero had a night to forget. Although he made a couple of important saves, he looked unconvincing with set pieces and was then caught out just after the hour, rushing out of his box and handling the ball as Wilson tried to get around him.
The red card came out, leaving United facing an uphill battle, particularly given his replacement Grant got nowhere near any of Derby's penalties.
United turn their attentions back to the Premier League on Saturday and will hope to bounce back from their 1-1 draw with Wolves by defeating hosts West Ham. Derby will be back in the Greater Manchester area the same day, facing Bolton Wanderers in the Championship.