Goals from Cristiano Ronaldo, Ryan Giggs and Nani booked Uniteds place in the Carling Cup fourth round, but the 3-1 victory over Middlesbrough was marred by a potentially serious injury to Rodrigo Possebon.
The Brazilian midfielder was carried off midway through the second half following a horror tackle from Emanuel Pogatetez who was rightfully dismissed for the offence. Earlier, Ronaldos 25th minute header was cancelled out by substitute Adam Johnsons volley after the break. Giggs calmly put United ahead late on, before Nani slotted home a clincher in the fifth of nine minutes of injury time.
United fans have become accustomed to seeing many of the Reds budding young stars when the Carling Cup comes round, but with a number of first team squad members needing to sharpen up their match fitness, Sir Alex opted for a mix of youth and experience in his starting XI. There were debuts for goalkeeper Ben Amos and striker Danny Welbeck, as well as first competitive starts for full-back Rafael da Silva and midfielder Rodrigo Possebon. Ryan Giggs skippered the side, which also featured a host of first team regulars including Cristiano Ronaldo in his first start of the campaign - Nemanja Vidic and Anderson.
United began the brighter with Giggs and Ronaldo looking particularly menacing, the former almost fashioning a 3rd minute opening for the onrushing Welbeck. But Brad Jones was alert to the danger and came out to punch clear. Soon after, Nani stung the palms of Jones with a fizzing effort, before clipping a near-post effort wide after an impressive build-up.
Further neat interplay involving Welbeck, Ronaldo and Giggs led to a corner and a subsequent opening goal for the Reds on 25 minutes. And it was a familiar name on the scoresheet as Ronaldo held off the attentions of Digard to head home Giggs inswinger.
The hosts almost doubled their lead three minutes later after a marauding run from Anderson down the left resulted in Jones saving Welbeck's back post effort with his feet. The game had developed into a lively encounter with the Reds dominating proceedings. But with Stewart Downing in their side, Gareth Southgate's men always posed a threat from set-pieces and it was the wingers left wing centre which forced Ben Amos into action for the first time, as he dived to his left to claim David Wheaters goalbound header.
A brilliant backheel from Rafael into the path of Welbeck, who slipped the ball to Ronaldo, almost resulted in a second United goal as half-time approached, but Jones parried the wingers fiercely struck low shot. He was forced into action straight after the restart, saving well from Welbeck after the striker had collected OShea's ball over the top.
The Boro stopper stooped low to his right to grasp Nanis 53rd minute shot and was no doubt pleased to see the Portuguese international overhit his pass as he looked to put either Welbeck or Ronaldo through on goal soon after. United were made to rue those missed opportunities on 56 minutes when, against the run of play, Boro drew level. Gary ONeills high ball into the area was headed clear by Vidic, but only to the feet of substitute Adam Johnson whose first time volley skimmed past Wes Brown and crept inside Amos right-hand post.
It was a bitter blow for United, but worse was to follow when they lost Possebon after Pogatetz's shocking lunge. A gaping wound displayed the external damage to Possebons right leg, but the distress etched on the Brazilian's face as he was given oxygen suggested it could be far more serious.
Quite understandably the Reds temporaily lost their momentum, but they regained the lead 11 minutes from time when Giggs took full advantage of substitute Chris Riggotts slip and nonchalantly clipped the ball over Jones. He went close to adding what would have been a brilliant third three minutes later, but Wheater headed his flicked shot off the line.
All three United subs - Carlos Tevez, Darron Gibson and another debutant Manucho - saw efforts go begging in the closing stages, before Nani capitalised on another defensive howler, this time from Wheater, and slotted home the third to complete, Possebon's injury aside, a hugely satisfying night for the Reds.
UNITED: Amos; Rafael, Brown, Vidic, OShea; Nani, Anderson, Possebon (Gibson 72); Giggs (c) (Manucho 84), Ronaldo (Tevez 61), Welbeck. Subs not used: Zieler, Cleverley, Gray, Eckersley.
BORO: Jones; Hoyte, Wheater, Pogatetz (c), Taylor; ONeil, Digard (Riggott 72), Shawky (Johnson 46), Downing; Alves (Emnes 84), Aliadiere. Subs not used: Turnbull, Arca, Walker, Craddock.
Booked: Johnson. Sent off: Pogatetz
Attendance: 53,729
