A difficult season for the Old Trafford giants continued on Sunday as they deservedly lost to the league leaders in a one-sided encounter at Anfield.
United were level at half-time after Alisson Becker's blunder saw Jesse Lingard cancel out Sadio Mane's opener, but Liverpool's pressure eventually counted as substitute Xherdan Shaqiri's deflected brace secured a 3-1 win.
It leaves Jurgen Klopp's men an eye-watering 19 points ahead of United after just 17 matches, but the 11-point gap to the Champions League spots is arguably even more concerning.
Asked if he was confident of making up that margin, Mourinho said: "Yes, I think (we can).
"What gives me that belief? It gives me the belief that we are going to make much more points in the second part of the season than we did in the first part.
"I know we lost some other matches but we played away at Liverpool, Chelsea and Manchester City - probably the three best teams apart from Tottenham.
"But we play with them away. I think we have more possibility to get more points in the second part of the season than the first part."