A double injury blow to Norwich City's midfield capped a miserable Capital One Cup fourth round exit on Tuesday night at Old Trafford.

Javier Hernandez's clinical double in the opening 55 minutes had already propelled the Canaries towards the exit door before Phil Jones and Fabio da Silva struck late on to seal Norwich's fate, but of far greater concern for the club's Premier League campaign was the second half departures of Robert Snodgrass and Nathan Redmond.

Snodgrass was stretchered away wearing an oxygen mask and his head in a protective support brace after a sickening aerial collision with Rafael Da Silva. Manchester United keeper Anders Lindegaard immediately put a clearly-dazed Snodgrass into the recovery position inside the Reds' six-yard box after his head appeared to catch Da Silva's calf when he fell awkwardly to the ground. Medical staff from both clubs tended to the stricken midfielder for 10 minutes before he was carried away to warm applause from all four corners of the stadium, but things got even worse for Norwich when Redmond pulled up clutching his left-hand side.

The England Under-21 international headed straight for the tunnel and treatment, paving the way for a second Capital One Cup appearance for Josh Murphy.

City may already have harboured a sense of grievance after Hernandez had slotted a first half penalty past Mark Bunn - given when Leroy Fer was adjudged to have clipped Adnan Januzaj tight to the Norwich touchline. Johan Elmander led a deputation to referee Kevin Friend regarding the generous nature of the award, but there was no disputing Hernandez's clinical take to send Bunn the wrong way from the spot.

Nor could the Canaries seek solace in any wrong-doing for the Mexican's second ten minutes after the interval. Hernandez rose unchallenged between both Sebastien Bassong and Ryan Bennett before reacting quickest following Bunn's superb initial reaction stop to slam into the roof of the net.

Snodgrass was one of three starters retained from the weekend's draw against Cardiff, with Bassong and Fer also pressed into service. Wes Hoolahan returned as Elmander's chief support, but Ricky van Wolfswinkel (foot) and Alex Tettey (ankle) were not risked.

Fer left an early calling card on Tom Cleverley which allowed Ashley Young to potentially test Bunn only for City's sturdy four-man wall to stand tall. United looked to push Chris Hughton's men back in the early exchanges with Wilfried Zaha keen to impress on his first senior start since a summer move from Crystal Palace. Norwich attempted to edge forward to probe deep in the hosts' half but Snodgrass' lift for Elmander was anticipated by Rio Ferdinand. Hernandez was fractions from opening the scoring in the 12th minute when he rolled Bennett but Bassong scrambled behind. Bradley Johnson's intervention then averted a certain goal from the resulting corner when he diverted Ferdinand's flick up and over from under the shadow of his own cross bar.

David Moyes' side surged forward in the aftermath with Bunn then forced to claw away Zaha's driven cross. Referee Friend intervened to City's chagrin when he pointed to the penalty spot after Januzaj went over after tangling with Fer on the byline – Hernandez making no mistake. Norwich's keeper pouched Hernandez's glancing header with the Mexican's movement and sheer intent a troubling feature of the opening quarter. Bennett tested Lindegaard for the first time in the tie with a header from 16 yards that reared up at the United stopper from Snodgrass' whipped centre. Norwich's collective pressing appeared to drop in intensity as the half elapsed, with United enjoying a comfortable passage through large swathes of central midfield to service Young and Zaha.

The wonderfully gifted Januzaj had Bunn grasping with a curling left-footer from fully 25 yards that shaved his right-hand post – the young striker's supreme confidence underlined by his apparent licence to roam in front of City's back four.

Hernandez doubled United's lead during City's most productive spell immediately after the interval, when both Fer and Elmander had threatened inside the six-yard box before the Canaries' night began to unravel with a double injury blow killing the visitors' gathering momentum. Snodgrass' brave header tested Lindegaard but the Scot was indebted to the Dane's quick-thinking as medical staff from both clubs raced onto the pitch. Anthony Pilkington was introduced after the lengthy delay before Redmond hit the brakes during a burst down the right flank. The teenage midfielder grasped his left-hand side as he was led away down the tunnel. Moyes rather cruelly opted to introduce Wayne Rooney but it was two of United's young guard who delivered the final blows.

Manchester United: Lindegaard, Da Silva, Jones, Ferdinand, Hernandez, Vidic, Young, Cleverley (Anderson 80), Buttner, Zaha (Rooney 78), Januzaj (Fabio da Silva 90). Subs (not used): Giggs, Smalling, Valencia, Amos.

Bookings: None

Goals: Hernandez (20, 54), Jones (88), Fabio da Silva (90).

Norwich: Bunn, Whittaker, Bennett, Bassong, Garrido, Redmond (Murphy 76), Fer, Johnson, Snodgrass (Pilkington 65), Hoolahan (Hooper 89), Elmander. Subs (not used): Martin, Howson, Becchio, Nash.

Bookings: None.

Goals: None.

Time added on: 3 minutes / 11 minutes

Referee: Kevin Friend (Leicestershire)

Attendance: 58,663