Manchester - Jose Mourinho was left red-faced amid fresh talk of a rift with Paul Pogba as Manchester United crashed to a shock penalty shoot-out defeat against Frank Lampard's Derby in the League Cup on Tuesday.
READ: Pogba not to captain again under Mourinho - reports
Just hours after Mourinho reportedly told unsettled star Pogba that he would never captain the team again, there was a bitter pill for the United manager to swallow as second tier Derby sprang a major surprise in the third round at Old Trafford.
Juan Mata had put United ahead in the opening moments, but Harry Wilson equalised and, after the hosts had goalkeeper Sergio Romero sent off, Jack Marriott gave Derby the lead with just five minutes left.
Marouane Fellaini headed United's equaliser deep into stoppage-time to make it 2-2, yet even that couldn't dig Mourinho out of trouble.
After Derby scored eight successive kicks in the shoot-out, United defender Phil Jones saw his effort saved by Scott Carson to give the Rams an 8-7 win.
It was a sweet moment for Derby boss Lampard, who enjoyed so much success working under Mourinho during their time at Chelsea.
But the apprentice's victory over his teacher was a painful blow to Mourinho, who has endured a troubled time since the end of last season and had to watch as Lampard danced jubilantly with his players on the pitch.
After squabbling with United's hierarchy over their failure to sign the targets Mourinho wanted, he has become embroiled in a feud with Pogba amid increasingly alarming results.
Defeats against Brighton and Tottenham, coupled with Saturday's draw against Wolves, have left United off the pace in the Premier League and now they are out of the League Cup.
It was a downbeat conclusion to a torrid day for United after relations between Mourinho and French World Cup winner Pogba reportedly hit a new low.
Pogba is believed to have been informed in front of team-mates that he does not embody what the club is about, so will no longer act as captain when regular skipper Antonio Valencia is absent.
The 25-year-old infuriated Mourinho after the Wolves match when he insisted United should "attack, attack, attack" in what was perceived as a dig at the manager's conservative tactics.
Asked just before kick-off about Pogba's absence from the squad, Mourinho insisted the former Juventus star had been "rested".
Pogba still turned up at Old Trafford, watching from a private box, but disappeared before the shoot-out.
The Pogba row overshadowed a superb achievement by Lampard, who only took his first managerial role at Derby in the close-season.
If Lampard was a reminder of better days for Mourinho, the United manager was briefly lifted again thanks to Mata's third minute opener.
Romelu Lukaku's clever dummy let the ball run to Jesse Lingard and his pass reached Mata, who swept a cool finish into the far corner from just inside the area for his first at Old Trafford for 12 months.
But Derby had United on the ropes with their slick passing.
Lampard's side were rewarded for their enterprising play in the 59th minute when on-loan Liverpool winger Wilson powered a fine free-kick past Romero.
Wilson was tormenting United and another of his dangerous raids in the 67th minute led Romero to sprint out of his area and block with his hand, earning a red card that forced Mourinho to send on former Derby keeper Lee Grant for his debut.
Lukaku hit the woodwork as United tried to respond, but Derby made the most of their numerical advantage to snatch the lead in the 85th minute.
Mason Mount's initial shot was saved by Grant, but, as United's defenders stood and watched, Marriott reacted alertly to head in from close range.
Fellaini came to United's rescue five minutes into stoppage-time when the Belgian converted Diogo Dalot's cross with a close-range header, however that was only delaying Mourinho's misery.