By ESPNSTAR.com staff
Current league leaders United widened the gap at the top of the table to six points after they beat nearest challengers City 3-2 on Sunday, with a Wayne Rooney brace and a last-minute winner from Robin Van Persie enough to secure all three points against last season's champions.
The Red Devils have the chance to go a massive nine points clear at the top of the table if they emerge victorious from their clash against Sunderland and City fail to overcome a tricky looking tie at St James Park against Alan Pardew's Newcastle United.
And Rafael has called on his side to just concentrate on using the psychological boost from their derby win to motivate them to get all three points against Sunderland.
"It's really important we get the result against Sunderland," Rafael was quoted as saying by the official Manchester United website.
"We did a very good job last week, everyone knows that but we need to keep our momentum going if we're going to get our title back.
"It's been a great week in training for us - beating City was a big boost mentally for us.
"And the way the game went and how we won was a great feeling and the result has motivated everyone.
"When you win a big game like the derby and win it in the way we did it's just such a good feeling.
"Everyone's confidence is very high, but it's important we don't take our foot off the pedal and we keep things going."
Rafael's team-mate Phil Jones echoed the Brazilian's sentiments and warned that Sunderland would not prove to be easy pickings for the Red Devils.
"Sunderland is another really important game for us," Jones declared.
"They're fighting for points at the other end of the table so we don't expect it to be easy at all, but we have to make the most of the position we're in."
Jones also revealed that manager Sir Alex Ferguson had clearly outlined that his side's short-term goal would be to end the year on a high.
"The manager talks a lot about the Christmas period being one of the toughest spells of the Premier League season," Jones added.
"To be in a strong position at the turn of the year is vital. We've put ourselves in a good position and we need to keep it going now."
United will take on Sunderland boosted by the return of influential defender Nemanja Vidic in the squad, although both centre-back Jonny Evans and midfielder Shinji Kagawa are ruled out for the clash.