José Mourinho has described Romelu Lukaku as “untouchable in my team”, with the Manchester United manager saying he has to protect his players when they deserve it.

After the 1-0 win against Tottenham Hotspur at Old Trafford on Saturday, Mourinho expressed disappointment that Lukaku had not been given vociferous support. The centre-forward created Anthony Martial’s 81st-minute winner and Mourinho also pointed to how the Belgian presented difficulty for Toby Alderweireld and Jan Vertonghen.

“The fans are the fans and I also told [on Saturday] that the fans pay for their tickets and are free to express themselves the way they want to express,” Mourinho said. “But my job, when I feel they deserve it, is to protect my players. Romelu is one of the players that should be untouchable in terms of the respect of everyone. It’s not one goal or the ball goes against the post or a save by the opposition keeper that can make Romelu’s contribution below the top level.

“He is playing extremely well for us and yes I have to protect my players when I feel they deserve it. And Romelu always deserves it because what he does for the team is fantastic. Playing football for a striker isn’t just about scoring goals. So for me [he is] untouchable in my team and I think he should be untouchable in support from the fans. But fans are fans, they pay the ticket and do what they want. As a manager I feel duty to protect my players when I feel they deserve it.

“Ask Vertonghen and Alderweireld if he was quiet, and they are some of the best centre-backs in football. I don’t think he’s quiet at all. The point is scoring or not scoring because in the end that is what people analyse sometimes.”

United welcome Benfica in Tuesday’s fourth Champions League Group A match as leaders with maximum points. If United win they are guaranteed qualification for the knockout stage. They go to Chelsea on Sunday in the Premier League but Mourinho said: “Nobody here thinks about another match than Benfica. Nobody here thinks about Chelsea. So it’s just Benfica, Champions League and only Champions League.”

On the achievement of potentially qualifying after four matches, Mourinho said: “Manchester United was eliminated by Basel and PSV Eindhoven [in the group stages in 2011 and 2015 respectively] but I think it is quite a logical consequence of evolution. We played the Europa League and won it. My team are now playing in the Champions League and we are now much better than last year or three years ago.”