And United's failure to tie down the 18-year-old to a new long-term deal has opened the door for Manchester City to potentially launch a counter offer for the Belgian playmaker.
Januzaj sparkled on his Premier League debut, impressing David Moyes in a 25-minute second-half cameo in the 2-0 win over Crystal Palace.
But the teenage midfielder has been locked in talks with United for the past six months with no end in sight.
And the report claims City are tracking developments with Januzaj's current deal set to expire at the end of the season.
He's believed to be requesting improved terms to reflect his step up to the first team as well as guarantees that he'll be involved in senior matches over the course of the season.
United suggested they would be willing to loan him out to a Championship club earlier this summer, amid interest from Blackburn. But Januzaj is eager to play first-team football in the Premier League for United, and plans for a loan move have now been ditched.
Moyes remains confident that the teenager will put pen to paper on a new contract, and with City waiting in the wings, he'll be looking to get it wrapped up sooner rather than later.