Sunday’s hard-fought 2-0 win over Everton at Old Trafford moved the Reds 12 points ahead of Manchester City with 12 games left.
But Rafael says the players are determined not to look too far ahead after the experience of last season, when United relinquished an eight-point lead with six games remaining.
“We just have to stay focused and play as we have been doing,” the Brazilian told MUTV. “We know what happened last year but we have a lot of experienced players here so we'll look to keep improving and keep playing well.
“[Sunday] was a very important win. Everyone talked about us losing the title against Everton last season, so we all worked hard to beat them. It was good to keep a clean sheet but the most important thing at this stage is the points.”
United can now look forward to Wednesday’s trip to the Bernabeu to face Real Madrid in the first leg of a blockbusting Champions League last 16 tie.
“Now we can think about Real,” Rafael said. “It’s an amazing game and we will get some rest and then get ready for that game.”