Values and philosophies are important in football, especially in the FA Cup, but this was a firm reminder that sometimes individual quality can make all the difference. Millwall worked heroically hard here at White Hart Lane this afternoon, aiming for their fourth Premier League scalp of a remarkable cup run. But they ended up being steamrollered and, eventually, embarrassed by Spurs, losing 6-0.

It was a fair reflection of the difference in skill between the two sides, but not of their efforts. This is what happens when the second-best team in the country comes up against the sixth-placed team in League One.

This match was ultimately decided by Heung-Min Son, Spurs’ striker who is not even first choice here. He scored a hat-trick, starting with two brilliantly precise finishes, one with each foot, either side of half-time. Son is a £22million player and that, in short, is the difference between the two teams. That is why Spurs will be going back to Wembley for the semi-finals next month while Millwall fight to get back into the Championship.

As hard as Millwall worked, Spurs were running through them by the end, scoring their last three goals in the last 18 minutes. Even Vincent Janssen, on as a second-half substitute, scored in open play for the first time since his £17million move to Spurs last summer.

Son and Janssen have been squad players this season but they could be crucially important over the final stretch of the season. Because the one bad point of this otherwise perfect afternoon was Harry Kane being forced off after just seven minutes, after painfully turning his right ankle under an early tackle from Jake Cooper. If it is as bad as the ankle sprain he suffered in September, as Pochettino fears, he will barely play again for Spurs this season.

Millwall came to White Hart Lane to fight for every 50-50, as Kane found to his cost. He was shooting from a tight ankle when Jake Cooper jumped in to block him. As Kane landed, Cooper’s challenge turned Kane’s right ankle and he immediately knew he had to limp off.

Despite that disruption, Spurs dominated possession, as they were always going to. They peppered the goal of Tom King, Millwall’s stand-in keeper, sensing him to be vulnerable and poor with his hands. He spilled two shots from Harry Winks and it took some desperate defending to stop him from getting exposed for so long.

Millwall even had a half-chance to take what would have been a very unlikely lead. Lee Gregory received a long-ball and held off Eric Dier, laying the ball back to Morison. He spied an angle towards the top corner but curled a difficult finish wide.

Tottenham 6 Millwall 0 player ratings Show all 22 1 /22 Tottenham 6 Millwall 0 player ratings Tottenham 6 Millwall 0 player ratings Michel Vorm – 5 out of 10 It was a quiet day at the office for the keeper due to very few attempts from the Millwall forwards. Getty Images Tottenham 6 Millwall 0 player ratings Eric Dier – 6 out of 10 Had a relatively straight forward day at the back, with few very Millwall moves causing him an issue. Getty Images Tottenham 6 Millwall 0 player ratings Toby Alderweireld – 6 out of 10 A disciplined display from the central defender. Did his job and held his shape at the back. Getty Images Tottenham 6 Millwall 0 player ratings Jan Vertonghen – 6 out of 10 Defended bravely and began moves from the back. Read the game well. Getty Images Tottenham 6 Millwall 0 player ratings Kieran Trippier – 7 out of 10 His assist for Son’s goal was sublime, as were the rest of his deliveries into the danger zones throughout. Getty Images Tottenham 6 Millwall 0 player ratings Victor Wanyama – 6 out of 10 Battled throughout and was a key element to Tottenham’s moves going forward. Getty Images Tottenham 6 Millwall 0 player ratings Harry Winks – 7 out of 10 Oozes confidence for a young lad and it was good to see taking shots on goal. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Ben Davies – 7 out of 10 Was charging up and down the wings, which provided Spurs with the width that they required. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Son Heung-min – 9 out of 10 The hat-trick hero was on fire today. His movement, work rate and finishing were all spot on. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Dele Alli – 7 out of 10 His goal marked his 16th of the season. His positioning was spot on today and he was always making space going forward. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Harry Kane – N/A Went off in the early stages of the game after losing his balance and appearing to injure his ankle. AFP/Getty Tottenham 6 Millwall 0 player ratings Tom King – 3 out of 10 Made a handful of important saves, but it’s never a good day when you concede six. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Shaun Cummings – 4 out of 10 Defended very narrowly, which allowed Spurs to cause damage in the wide areas. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Byron Webster – 5 out of 10 Struggled to cope with Tottenham's pace going forward. CameraSport via Getty Images Tottenham 6 Millwall 0 player ratings Jake Cooper – 5 out of 10 Heung min-son made his life very difficult. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Tony Craig – 5 out of 10 Defended bravely, but simply failed to contain the Spurs strikers. Getty Images Tottenham 6 Millwall 0 player ratings Jed Wallace – 6 out of 10 He tracked back and worked hard defensively, but failed to show any ability going forward. Getty Images Tottenham 6 Millwall 0 player ratings Ben Thompson – 5 out of 10 Lost the battle in the midfield and this allowed the opponents to dominate the play. Getty Images Tottenham 6 Millwall 0 player ratings Shaun Williams – 6 out of 10 His deliveries up the field were impressive, but they lacked the final product. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Aiden O’Brien – 5 out of 10 Was forced to drop deep due to the quality of the Spurs defence. He was marked out of the game. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Lee Gregory – 6 out of 10 His work rate was faultless, but he did not have enough time on the ball to actually make an impact. Getty Images Tottenham 6 Millwall 0 player ratings Steve Morison – 6 out of 10 Looked the most dangerous prospect for Millwall going forward. Getty Images

But when Spurs took the lead, to Millwall’s frustration, it was gifted to them by the most avoidable error. Byron Webster and Jake Cooper jumped for the same ball and collided. Dele Alli took the ball down and it fell to Eriksen, on as a substitute for Kane, to put it in on the turn.

It was one of those moments that underlined that, for all Harris’ brilliant work, there was an obvious gulf in quality between the two sets of players, one that no amount of motivation or organisation could bridge.

That was glaringly true with Heung-Min Son’s first two goals, scored either side of half-time, ending the game as a contest. Son’s first came five minutes before the interval, as Alli and Dier broke forward and passed to Son on the right. His first touch was poor but he shuffled back inside and curled the ball with his left foot into the far top corner of the net.

Son fires home his second goal for Spurs (Getty)

It was one of those moments that underlined that, for all Harris’ brilliant work, there was an obvious gulf in quality between the two sets of players, one that no amount of motivation or organisation could bridge.

That was glaringly true with both of Son’s first two goals, scored either side of half-time, ending the game as a contest. Son’s first came five minutes before the interval, as Alli and Dier broke forward and passed to Son on the right. His first touch was poor but he shuffled back inside and curled the ball with his left foot into the far top corner of the net.

Dele Alli scores Tottenham's fourth goal (Getty)

It was a brilliant goal but his second, 10 minutes after the re-start, was even better. Kieran Trippier chipped a hopeful long ball over the top of Cooper. Son ran onto it, watched the ball over his shoulder and volleyed it, this time with his right, into the net. After being taunted by Millwall fans about South Koreans selling DVDs, it was a perfectly dismissive response.

At 3-0 Millwall’s resistance was over and Spurs could easily run through them. Dele Alli scored the fourth, putting Eriksen’s pass in at the far post after he was released by Kieran Trippier, an intricate incisive move.

Vincent Janssen's teammates rush to celebrate with him after scoring his first goal for Spurs from open play (Getty)

The biggest surprise was yet to come, though, when Janssen, on as a substitute, found the bottom corner of the net from Son’s pass, for an open-play goal that many thought would never come.