United won the league last season with Liverpool way back in seventh, but the club's fortunes have flipped this campaign with United in sixth position – a full 11 points behind second placed Liverpool who are contending for the title.
When asked by the club's in-house magazine, Inside United, whether it was hard to see their Manchester rivals City above them in the table, Rooney couldn't help but bring up Liverpool's form which he finds even more bothersome.
"To see City doing well, and particularly Liverpool, is really difficult," he admitted to the magazine.
"It's not nice when we know we are capable of being up there challenging and we haven't been doing that this season.
"However, it means we have to step up and get back up there because the feeling we've had this season is not a nice feeling at all to have.
"We have to keep working, keep progressing and finish the season stronger."
Liverpudlian Rooney grew up as an Everton fan and has made his disdain for the red half of the city known in the past.
In 2009 he told the official Manchester United website: "I grew up as an Everton fan hating Liverpool - and that hasn't changed."
The United website later removed the comments.
Last month Rooney committed his future to Manchester United when he signed a four-year contract extension worth a reported £300,000 a week.
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