Kane says Spurs must pick themselves up quickly to ensure a top-four finish and ensure they have Champions League football when they move into their new stadium next season.
"We are going to invest the basic [amount required] to improve our squad - find a replacement for Michael Carrick, if Marouane Fellaini leaves we are going to need a replacement for Marouane Fellaini", he added.
When asked how much investment United need to challenge City, Lukaku told reporters: "I don't know, you'd have to ask the manager".
United and Chelsea have acquired a win apiece this campaign and the prospect of a final between them appears a distinct possibility.
"If you look at games we have played against the top six, we have won a lot of them so when we played against Tottenham we were confident as well".
United have demonstrated the fortitude to come from behind to beat Chelsea, Manchester City and now Spurs in the past two months but also lost against struggling Newcastle and West Brom in that time, and Mourinho wants greater consistency.
"I think we showed against the [likes of] Real Madrid and all the other games that we can do it".
"But if they have the team they have and if they are going to invest on top of the team they have, of course it is going to be very hard for us". "That is great. It is something that we wanted and now we have four games to go in the league where we have to perform really well, and then the final".
"We came here to create a winning mentality", he said in a post-match interview with the BBC.
Paul Pogba really did cross superbly as the ball dipped right onto Alexis Sanchez's head with such precision that all he had to do was place it.
And his cross was inch-perfect for Alli to apply the finishing touch for his 13th goal of the season. "We let ourselves down, it's very disappointing".
"We were dominant from the first minute and it only looked to be going one way".
For all the talent Tottenham possess in every area of the pitch, silverware keeps eluding them and that's become a frustration for the players.
And the Chilean was involved again for the victor 28 minutes from time when his ball across the face of the area fell perfectly for Herrera, whose low effort beat goalkeeper Michel Vorm.