London: Derby County manager Frank Lampard piled more misery on his former Chelsea boss Jose Mourinho as the Rams beat 10-man Manchester United 8-7 on penalties, while Manchester City cruised into the last 16 of the League Cup on Tuesday.
Mourinho paid the price for making nine changes in a thrilling 2-2 draw at Old Trafford before spot-kicks with Paul Pogba rested on another day dominated by the Frenchman's frosty relationship with his manager.
Phil Jones finally missed from the spot after 15 successful penalties in a high quality shootout.
"The penalties come, somebody has to miss. I knew we were going to be in trouble with Jones," said Mourinho in a barb at one of his own players.
Mourinho also confirmed Pogba has been stripped of the United vice-captaincy after criticising the Portuguese's tactics in a 1-1 draw at home to Wolves on Saturday.
"The only truth is I made the decision of Paul not to be the second captain anymore," added Mourinho.
Early on it seemed like the United boss would get a positive response from his much-changed side as one of Lampard's former Chelsea team-mates Juan Mata slotted home the opener after just three minutes at the end of a fine team move.
However, an unchanged Derby side struck back after the break thanks to a wonderful free-kick from on-loan Liverpool striker Harry Wilson.
Moments later, United goalkeeper Sergio Romero saw red for handling another Wilson effort outside the area.
The visitors made the man advantage count when Jack Mariott headed home five minutes from time, but Marouane Fellaini looked to have saved Mourinho's blushes with a towering header deep into stoppage time.
However, substitute United 'keeper Lee Grant failed to stop any of Derby's penalties and Jones finally faltered to compound a bad start to the season for Mourinho's men, who already trail Premier League leaders Liverpool by eight points.
"It's right up there," said Lampard when asked how the trumph compared to his highs as a player.
"You feel like you've done your work when you come to Old Trafford and go against Jose Mourinho and world class players. The feeling I got from it was immense, it's an incredible feeling for me."