Patrick Vieira and Roy Keane, talismanic midfielders for their respective teams, led from the front as they won trophy after trophy, medal after medal in golden periods for Arsene Wenger and Sir Alex Ferguson.
But both were driven to win, and their feisty approach to playing the game often led to the odd scuffle...except when they faced each other, and fireworks were let off. The most infamous fight between the two was the incident in the tunnel before United took on the Gunners at Highbury in 2005.
Yet despite their differences, Vieira and Keane agreed to meet each other once again in a documentary for ITV, which can be viewed here.
Gabriel Clarke was asking the questions to begin with, and dangled the carrot in the front of their faces by asking them to name the biggest weakness of their nemesis. Vieira alluded to Keane's ability to "lose his head, forget about the game and he can be reckless" - somewhere, Alfe Inge Haaland nods in reluctant agreement.
Keane, somewhat hilariously, said Vieira's biggest strength was his toughness - but his biggest weakness was that he wasn't as tough as the Irishman. Keane begins the discussion by saying "usually when you play against certain teams like Arsenal, there is usually one or two players you might like...but I don't remember liking anybody at Arsenal," which summed up the hatred Keane had for the Gunners.
Vieira suggested that United couldn't handle being challenged by Arsenal, and they both agreed that Wenger and Ferguson almost encouraged them to hate each other by refusing to play the rivalry down.
One of the most interesting sections was when Clarke asked who both players who the best manager they played under was. Vieira, unsurprisingly, plumped for Wenger. Keane, on the other hand, said; "Without a doubt, Brian Clough," almost luring Clarke into the question "Not Sir Alex?". Keane played it with a straight bat, saying "You asked me the question, I answered it", showing the broken relationship between Ferguson and Keane has still not been repaired.
Keane took another swipe at Ferguson after Clarke read out a quote from the former United boss. "Pounding every blade of grass, competing as if he would rather die of exhaustion than lose he inspired all around him. I felt it was an honour to be associated with such a player."
"Stuff like that almost insults me. What am I supposed to do? Give up? Not cover every blade of grass? Not do my best for my team mates? Not do my best for the club? I actually get offended when people throw quotes like that about me. It's like praising the postman for delivering letters. He's supposed to, that's his job isn't it? My job was to win games for Manchester United."
The show then moved onto selecting a combined Arsenal-Man Utd XI. Firstly, Keane gave his United team of players he played with (Schmeichel; Parker, Pallister, Stam, Irwin; Beckham, Keane himself, Ince, Ronaldo; Van Nistelrooy, Cantona) Vieira said he would've had Paul Scholes in the midfield, whilst Keane said he couldn't leave Beckham or Ronaldo out at the expense of United great Ryan Giggs.
Vieira's Arsenal XI was Seaman; Lauren, Campbell, Adams, Cole; Ljungberg, VIeira himself, Petit, Pires; Bergkamp, Henry. The choice of Lauren over Dixon was suprising, but Vieira justified it by saying Lauren was better on the ball, whilst he also expressed his shock that Arsenal allowed Cole - someone Vieira thought would be a future England captain - to leave to a big rival in Chelsea.
The two then combined their teams, but disagreed heavily on who should play at left back. The choice was Dennis Irwin or Ashley Cole, and they simply couldn't agree. The rest of the team was Schmeichel; Lauren, Stam, Adams, Cole/Irwin; Pires, Vieira, Keane, Ronaldo; Cantona and Henry - some big names were left out, including Dennis Bergkamp, Ruud van Nistelrooy, David Beckham and Sol Campbell, showing just how great the two teams were in that era.
Without giving too much of the show away, the two players acknowledged that they brought out the best in each other, and that their rivalry spurred their team mates on. The documentary showed the good, the bad and the ugly of their rivalry, from being parts of treble winning and invincible sides to their parts in numerous feuds between the two sides.
The two also stated that, whilst games between United and Arsenal are still entertaining, the animosity, the rivarly and the hatred has disappeared. Whilst many will say that Arsenal's recent dearth of trophies and United's recent domination are to blame, perhaps the departures of Vieira and Keane, which occurred within four months of each other, are the reason we don't see more fierce battles between the two clubs.