Tottenham and Manchester City have shared many qualities - a historical propensity for snatching defeat from the jaws of victory for one - over the years, but now they are poles apart, both in terms of their aims and paths they've taken to try and reach them.
Spurs, who broke their own record for fielding the youngest XI in the Premier League with an average age of a touch over 23 today, are trying to find an alternative way back into the top four after years of banging against a glass ceiling time and time again.
City, meanwhile, since the days of these two teams scrapping for a top four finish and less between them, have moved to a different stratosphere. Today they were bought back down to earth.
Spurs had won just one of their last nine meetings with City. They'd managed just five goals in the Premier League - a tally they would almost double by the end of the day. Manuel Pellegrini's side, although devoid of the creative talents of David Silva and the leadership of Vincent Kompany and Joe Hart, were heavy favourites.
Mauricio Pochettino called for his young troops to offer 'more dynamism' in the build up to this game and that's what he got, with more than a little encouragement from the Argentine coach himself on the touchline. Harry Kane, so desperate to end a 12-hour goal drought, squandered a couple of presentable chances after Spurs had swarmed forward in the hope of pressing for a mistake, although credit must be given to Willy Caballero for palming away one stinging effort in particular.
But while Spurs' energy was a hallmark of the game, so was Manchester City's assuredness when it came to carving chances. Unperturbed by the home side's high tempo, Manuel Pellegrini's side found space behind their opponent's pressing plan and created problems. Raheem Sterling tested Hugo Lloris twice in the first half while Aguero found space in the Spurs box only to see his close-range effort blocked.
It was Spurs' own enthusiasm that led to the first goal, but not in the manner they'd hoped. Miscommunication between Kyle Walker and Christian Eriksen led the ball directly into the path of Yaya Toure, who burst forward. His slide rule pass found Kevin de Bruyne, who now has three goals in his first three games for City. The visiting fans ironically chanted 'what a waste of money' as the Belgian basked in the glory of his goal. The hint of offside certainly didn't seem to bother him.
Despite their callous youth, there's a backbone to this Spurs side, who in recent years have wilted under the pressure against City. They just about weathered the storm before coming back fighting. Erik Lamela, fighting for his own future, ballooned a shot over from Ben Davies' low cross while Kane could have scored as well.
The equaliser came via slightly fortuitous circumstances. Walker, who was so far offside it was borderline criminal that he wasn't spotted, crossed low into the box, only for Caballero to block Son's effort from close range. The ball came out to Eric Dier, and with Manchester City seemingly dazed by the absence of the official's flag, the young defender-turned-midfielder jabbed a ball into the net from around 20 yards. Martin Demichelis earned a booking from referee Mark Clattenburg for his protestations.
That goal on the cusp of half-time appeared to inject a renewed sense of life into Spurs as they came out swinging for City, who had no response to the young pretenders.
Devoid of Toure's influence - the Ivorian came off to be replaced by Jesus Navas - Spurs were able to move forward more confidently, and it was Kane's persistence that led to the second goal just after the hour mark. The England forward won his side a free-kick out wide on the right, and Lamela's cross fell onto the head of Toby Alderweireld, who dropped his header into the net that Caballero had kindly abandoned.
City looked punch-drunk as White Hart Lane rocked and then it was Lamela's turn to apply the pressure with a penetrating run that forced another free-kick, which forced another goal. Eriksen's effort crashed off the bar and Kane was quickest to react. His sense of relief as the Spurs faithful sang his name was palpable.
This felt like a real moment for Pochettino and his young team. All season long they have played well and scarcely got the rewards they deserved. By the end everything seemed to fall into place; the inexperienced midfield duo of Delle Alli and Dier were snapping into tackles, Lamela strutted like the cockerel that looms over White Hart Lane and even Pochettino's subs were paying off, as new-boy Clinton Njie turned into space and teed up Lamela for Tottenham's fourth with ten minutes remaining. Delirious excitement doesn't do the noise made by the White Hart Lane crowd justice.
City, despite being without key players, were a shadow of the team that had started the season so well. It took its time but the lack of pace between Nicolas Otamendi and Martin Demichelis was exposed, and without Toure and Kompany they lacked a leader when the pressure was on. Pellegrini will face questions to his response after City fell behind too.
It's difficult to put this game into context. City hadn't lost by a three-goal margin since 2011 where Liverpool were their opponents while Spurs hadn't scored four against City since the 60's. The first half suggested that neither of those records was in danger.
Is this the start of something special for Tottenham? At the end of the summer window, Daniel Levy spoke of 'pragmatic player trading', of the need to find an alternate way to the top without spending big bucks. It's too early to tell whether Pochettino's "greater than the sum of its parts" approach will work in the long-term but when it clicks, on days like this, it's something special to behold.