Phil Jones missed the decisive penalty as Derby County heaped more misery on Jose Mourinho to dump Manchester United out of the Carabao Cup.
Mata broke the deadlock after three minutes, finishing off a smart United move to curl home into the bottom corner.
Derby should have equalised when Mason Mount’s delightful ball found Mason Bennett free eight yards from goal, but his finish was straight at Sergio Romero. And the Argentinian denied Harry Wilson with another top save as the Rams started the second half on top.
The Liverpool starlet would not be denied his moment though, striking a stunning free-kick from range to leave Romero rooted to the spot as it nestled in the top left corner for a deserved equaliser.
The United back-up goalkeeper could not stay out of the action and was rightly sent off for handling the ball outside the area as Wilson flicked the ball beyond him.
Marriott capitalised after Mount’s shot was saved, heading past Grant, but United were not done, as substitute Marouane Fellaini headed home a stoppage time equaliser to force penalties.
After 15 perfect penalties, Scott Carson saved Phil Jones’ penalty to secure a famous win for the Rams.
Here are five talking points from Old Trafford:
1. Lampard not Mourinho II
Frank Lampard admitted to being emotional taking his Derby side to Old Trafford to take on his former master Jose Mourinho.
And whilst the special one will have undoubtedly rubbed off on him throughout their time together, Lampard’s side was distinctly different to how you would imagine Mourinho approaching a similarly tricky away trip.
Adventure and bravery on the ball, Lampard’s Rams moved the ball nicely and carved open several openings.
Perhaps most telling was how his full-backs operated, with Craig Forsyth especially positive when picking up the ball inside his own half and driving forward.
The influence of Mourinho will be important in Lampard’s managerial journey but the former Chelsea star appears to be creating his own philosophy.
WATCH PICTURE HIGHLIGHTS OF MANCHESTER UNITED’S SHOCK EFL CUP DEFEAT TO DERBY COUNTY
2. Chelsea youngsters impress
Mason Mount received all the hype before kick-off with the Chelsea loanee dazzling on loan with the Rams.
But Fikayo Tomori is another gem from the Blues academy looking to take a step under Frank Lampard.
Mount sliced United’s back line open to find Mason Bennett wide open at the back post with Sergio Romero’s save denying him a famous assist. Tomori, too, made a big impact.
Romelu Lukaku was racing clear on goal and set to make it 2-0, but Tomori sprinted back just in time to nudge the Belgian and force him to drag his finish wide.
Maurizio Sarri will likely be sent rave reviews of the pair’s contributions at Old Trafford, with Lampard handling the pair’s development superbly.
3. Dalot can be whipped into shape
He can sure whip a ball in that Diogo Dalot.
No dwelling on it, working out if people are in better positions behind him, or holding it for an over-lapping run.
When the £19m Portuguese defender gets the ball on the right he launches it in the box… with zip and accuracy.
And when you have Romelu Lukaku is in your ranks, that’s a dangerous weapon to have in your arsenal.He’s also got a long-throw…
4. Pogba all smiles despite humiliation
Paul Pogba was in the stands sporting a smile as Manchester United hosted Derby in the Carabao Cup on Tuesday evening.
The Frenchman was present despite having yet another fallout with boss Jose Mourinho.
Just hours before United’s clash against Derby, the Portuguese informed Pogba he would never captain the side again.
Pogba was then absent from the squad that took on Derby on Tuesday, but Mourinho explained it was because he decided to rest the midfielder. Pogba was sat in the executive box in the Sir Alex Ferguson Stand alongside Andreas Pereira and Luke Shaw.
5. Martial sparkles
After flattering to deceive when afforded opportunities this season, Anthony Martial finally showed what he is capable of.
Dancing in from the left, he was key to opening up Derby and sparking movement throughout the United side.
A key take-on led to the opener from Juan Mata, with the French winger intelligent enough to roll it back across the pitch after forcing Derby to overload down his side.
The ability to go on the outside was also on display too: his delicate steps allowed him to shuffle to the byline inside the box before flicking a cross up and over Scott Carson to the unmarked Romelu Lukaku – but the Belgian incredibly headed over.
This was much more like the Martial that fans believe he should be at this stage of his career and, with potentially a run in the side as a reward, he might yet be a key part to Mourinho’s side.Download Our News App Here