Ed Woodward refused to sanction bids for the Croatian duo last summer, with their clubs demanding substantial figures for the World Cup stars.
Perisic and Rebic helped Croatia reach the World Cup final in Russia and saw their asking prices soar as a result.
Mourinho has been desperate to sign an attacking right winger for the last 12 months, but so far United have been unable to deliver.
The Mirror claim that despite Woodwards reluctance, Mourinho will renew Uniteds interest in Rebic and Perisic in January.
Mourinho is targeting a bust winter window after feeling he was not backed in the summer by Woodward.
The head coach publicly criticised the United transfer chief, insisting his side were in for a difficult season without new signings.
And Mourinhos prediction came to pass as United have endured a dismal start to the campaign.
Three Premier League defeats in their first eight Premier League games leave United eighth in the table.
Inter wanted £48million for Perisic last summer, but United refused to offer higher than £45m for the attacker.
And Woodward would not budge on Rebic either as Eintracht Frankfurt demanded £40m for his services.
Mourinho believes his side will be massively helped by the addition of either attacker.