Chris Smalling has admitted it would be painful for a whole year if Manchester United fail to defend their Premier League title and lose local bragging rights.
United have the chance to reclaim top spot and move three points clear of Manchester City by beating Smalling's former club Fulham at Old Trafford on Monday night.
Sir Alex Ferguson's men have nothing else to play for this season after crashing out of both domestic cups and enduring a disappointing European campaign.
Smalling is determined to win some silverware and would love to finish first in the Premier League once again after helping United become champions in his first season at the club last term.
The defender also believes that it is especially important to come out on top because it is City they are competing with in a tight race.
"We're both Manchester clubs. That's bragging rights for a whole year. We can't let that happen!" he said in the Daily Star.
"They are not used to playing for just one trophy at United. The Champions League is gone. We are all disappointed about that.
"But we have to make sure we get that Premier League trophy in the bag. It was great to win it last year, in my first season with the club.
"It would be even better to win two in a row, especially when you see people like Ryan Giggs and Paul Scholes have won it 10 or 15 times. It's not that they brag about it or anything, but it makes you think. We have to make sure we are on our toes all the time."
Smalling has shown his versatility at United by operating at right-back as well as centre-half, but he admits it is in the heart of defence where he would prefer to play.
The fine form of Jonny Evans has limited his opportunities in that position, but Smalling is not afraid of competition for places.
He said: "That just drives you on. The competition makes you raise your game. Jonny's come in and done really well. But I knew he was here when I came.
"You have to deliver each week.
"Long term I see myself as a centre-back, that is where I hope I will play, but I'll play wherever the manager asks me too.
"We had injury worries at the start of the season. But I'd only ever played centre-back when I joined, and I'm pretty sure that's where they see my future."
Smalling made the move to Old Trafford from Fulham and he insists he is still thankful to his former club for the role they played in his development, while he is expecting a tough game on Monday despite a 5-0 victory at Craven Cottage earlier in the season.
He said: "They don't get beat there 5-0 much, so they will be out to avenge that, I'm sure. Fulham can be a real threat.
"I do owe them a lot, especially Roy Hodgson. He really gave me my chance."