The decisions paid off brilliantly, with Rashford and Herrera scoring the goals and being the star performers at Old Trafford.
Manchester United midfielder Ander Herrera has been likened to Italian World Cup victor Claudio Gentile.
Mourinho's men continued to dominate possession during the early parts of the game.
Offering more mobility than Ibrahimovic, Rashford tormented Chelsea's defense all game and showed there is a bright future at United if the Swedish striker decides to end his stay at Old Trafford after just one year.
Manchester United's dominance against Chelsea on Sunday shocked even more than their win, but Ashley Young believes such a performance has been coming - and now the stand-in captain wants more.
However, Rashford continued to impress late in the first half and he did well to hold off Victor Moses and fired a cross in and it nearly ended up inside the goal after Gary Cahill's defelction.
However, the signs against the Red Devils weren't good for Chelsea. That cut the gap with United to one point with three games to play.
Herrera was also questioned on his handball in the lead up to Rashford's opener, insisting he had no intention of handling the ball.
Graeme Souness heaped praise on Marcus Rashford for his sparkling display for Manchester United against Chelsea on Sunday. Chelsea found a rare chance in the 60th minute as Eden Hazard delivered a cross, but it was too long for Pedro to connect with. The former Athletic Club playmaker is pleased to be in the thick of the action in Manchester, but with United's vast wealth and their penchant for colossal transfer deals - they have been heavily linked with £35m (£42m) Monaco midfield general Tiemoue Bakayoko - he knows he can not rest on his laurels.
Roberto Firmino scored Liverpool's winning goal for the second straight game as his team climbed back above Manchester City into third place. Manchester United continued to press Chelsea but the Blues were able to sustain their continued pressure.
While United's hopes of making the top four will be boosted by the win, the major impact will be felt in north London where Spurs will sense a chance to chase down Chelsea's four-point lead in the final six games of the season.