United are 15 points clear of Manchester City at the top of the table going into Monday's derby.
They have won 25 of their 30 league games this season, and Nani says that they were focused from that moment.
"We always want to bounce back when we lose something," Nani told the Daily Star.
"So what happened last year made us very focused on the league this year. I think we've been doing a good job and we want to make history.
"It's difficult to forget the gap but we will only relax when we know it's not possible for a team to compete with us."
United welcome City to Old Trafford on Monday at 8pm.