It is fair to say life without Sir Alex Ferguson has not gone to plan so far, with the reigning champions sat seventh in the Barclays Premier League as the campaign enters the home straight.
Such poor form has seen the pressure mount on manager David Moyes but there at last seems to be signs that things may be improving.
United progressed to the Champions League quarter-finals with a fine victory against Olympiacos on Wednesday, which they followed up securing a 2-0 victory at West Ham.
Next up is a home clash with City on Tuesday and the chance to derail their title challenge - an opportunity Rooney is relishing after a morale-boosting few days.
"I thought we played some really good stuff, moved the ball well and counter-attacked really well so we're really pleased with the win," he said.
"The Olympiacos game gave us a big lift in confidence and belief as well in ourselves.
"This was a good result for us going into the derby so we're looking forward to an exciting game and hopefully get a good result."
With Robin van Persie facing up to six weeks out, United could do with another man-of-the-match display from Rooney on Tuesday.
The 28-year-old netted a brace at Upton Park, with the second seeing him move onto 212 goals and usurp Jack Rowley as the third highest goalscorer in United's history.
It was, however, Rooney's first after just eight minutes that will live long in the memory as he sent the ball sailing over goalkeeper Adrian from 58 yards.
"You have to think quickly and, to be honest, I've tried it quite a few times throughout my career," he told the BBC.
"I haven't been lucky enough for one to go in and but today thankfully I caught the keeper off his line and went in."
Rooney's effort was reminiscent of David Beckham's wonder strike at Wimbledon in 1996 and, rather aptly, the former United midfielder was in the stands to witness the goal firsthand.
"I remember it, of course," he said. "It is one of the most iconic goals in the Premier League.
"That was a great strike and obviously there were two different goals, his was off the floor and mine was on the volley.
"It is always great to score a nice goal and I am really pleased."
While Rooney's goals made the headlines, he was quick to praise his team-mates, in particular the attacking support of Juan Mata and Shinji Kagawa.
"I think it is the first time we've probably both played in a more advanced role, together with him up behind," Rooney said of Mata.
"It worked well. Obviously Juan is a very talented footballer, got a good footballing brain and when he gets in positions you know as a forward you can make runs and he can see you.
"I think also Shinji Kagawa coming in played excellent as well. The two of them were causing West Ham problems."
Like United, West Ham are also back in action in midweek as they welcome Hull to east London.
It looks to be a vitally important match for the Hammers after suffering a third successive defeat against a United team James Tomkins believes they could have taken a positive result from.
"We're obviously disappointed, because the side that Manchester United put out was a team that we could have made the most of on Saturday," the centre-back told West Ham TV.
"Unfortunately, their qualities have obviously shown again with the two goals.
"The second one's unfortunate and the first is a great goal. We look at it ourselves as being a disappointing day."