But just as United fell into a lull as half-time approached, it was Scholes who sparked the game into life to continue a fine week for veterans coming out of retirement after Thierry Henry's goal for Arsenal on Monday.
Scholes, 37, had been relatively quiet up until that point on his first start since 22 May 2011, save for a whack on Mark Davies, but he was lurking at the back post to tuck in Rooney's cross after David Wheater had blocked Nani's centre.
It was his first goal for 32 matches since scoring on 22 August 2010 against Fulham, and it proved that on his second game back, a break from the game has done little to blunt his expert sense of timing.
Ferguson praises 'important' Scholes
The midfielder was later replaced, and similar to their second-half display against Manchester City last Sunday, Sir Alex Ferguson's side slid into periods of sloppiness with David Ngog guilty of not punishing them when he fired over from close range.
Rooney could not turn in Antonio Valencia's cross but only a desperate block by Rafael da Silva stopped Martin Petrov's shot, and the Brazilian also cleared Gretar Steinsson's looping header off the line.
While there was a goal between the two sides, it was far from comfortable for United but their fraying nerves held together when Welbeck latched onto Rooney's attempted through ball, although it looked like Wheater got the touch, and poked past Bogdan for his eighth of the season.
Unfortunately for United, Welbeck seemed to hurt his knee in stretching for the ball and they will hope he is fit for the trip to Arsenal next Sunday.
Carrick then collected Ryan Giggs's square pass to advance and almost passed the ball into the net from 20 yards to seal the victory.
Darren Pratley went close for Bolton late on, but there was no doubt who the evening belonged to and, as Scholes's fitness improves, the decision to return to playing could prove an inspired one.
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