The array of glorious goals, particularly from man-of-the-match Son and Eriksen, was a fitting way for Spurs to say farewell to Cup competition at White Hart Lane.
But Tottenham manager Mauricio Pochettino said Son hadn't complained about the chants after the match.
"We fancied ourselves heading into the game", he said.
'I thought we'd got away from all those things and for it to happen to someone like Seol is a disgrace. It's hard. It looks a similar situation to Sunderland.
"We can not cry, we have to try to be positive", Pochettino said.
"It's too hard, today, to give you a real level of how his ankle is". We need to assess him today it is hard to give you a real level of how he is. It was a similar action. After that, we will see.
- Son Heung-min left with the match ball, Harry Kane with a protective boot. "Before the scan, the doctor tries to immobilise the joint, with the boot and crutches - to try to avoid any [further] problems".More news: Criss Angel rushed to hospital after passing out during live magic show
"We knew we had to step it up a gear and we did". We have to be positive. "We respect them. It is clear how they play, very compact, clear in their idea how they manage the game". "It won't be an excuse if we don't win or achieve our aims because Harry is not in the team".
Aside from Son, manager Mauricio Pochettino is short of attacking options.
"In football you always need to be ready".
Millwall are now winless in their last 14 competitive games against Spurs - a run stretching back 78 years - and Alli was ecstatic with the professionalism shown. He had an opportunity today and scored.
Tottenham player ratings: Vorm 7; Dier 7, Alderweireld 7, Vertonghen 8; Trippier 8, Wanyama 8, Winks 8, Davies 7; Son 10, Alli 8; Kane 6. Son can never be sure of a starting spot but he has netted 13 goals this season.
Lord Ouseley, chairman of anti-racism group Kick It Out and a Millwall fan, told the Associated Press news agency: "If complaints are made they will have to be looked at to see if they have any validity to see if it stirs up racial hatred". It demonstrates Pochettino's lack of faith in Vincent Janssen that midfielder Christian Eriksen was preferred as Kane's replacement rather than the only striker on the bench. It's about the team performance.
Spurs clearly wanted this one over quickly and peppered stand-in Millwall keeper Tom King with shots on goal.