Mourinho has claimed Tottenham finishsing fourth without Harry Kane and Son would be the greatest achievement of his career.
Mourinho has won eight out of 14 games since being appointed Tottenham manager but has claimed he now has a massive job on his hands.
Spurs were recently beaten by Leipzig in the Champions League and take on Chelsea at the weekend in their pursuit for a top four finish.
Luck has not been on the side of Spurs as they have lost their most influential goalscorers recently due to injury.
Harry Kane was already out injured at the turn of the year and much recently Son was also ruled out long term as well after fracturing his arm.
Mourinho has now claimed a top four finish without his two best players would be his greatest achievement till date.
“Would a top-four finish be my greatest feat? In these circumstances, yes,” Mourinho told a press conference on Friday via Skysports.
“Sonny and Harry score the majority of Tottenham goals. If we manage to finish fourth without Harry and Sonny would be something incredible for the boys.
“We have to give everything we have.”
Mourinho would be counting on other members of his squad to step up and start scoring goals as the season gets to the latter stages.