Look at Manchester United's toxic rivalry with Arsenal at the turn of the century and there was bad feeling to be found wherever these two clubs crossed paths.
It was epitomised by Sir Alex Ferguson's personal vendetta against Arsene Wenger off the pitch and Roy Keane's running battles with Patrick Vieira on it.
So we shouldn't be surprised to learn that Ruud van Nistelrooy had an unhealthy obsession with Thierry Henry, to the point of sulking if the Arsenal player had scored, even if the Dutchman had been on target himself and United had won.
'He was just a ruthless, ruthless goalscorer. He lived for scoring goals,' recalled Van Nistelrooy's former team-mate Paul Scholes recently. 'Whenever he did or didn't score, the first thing he would do when we got on the team bus after the game was see if Thierry Henry had scored.
'If Henry had scored, he wouldn't talk to anybody for the full trip home because he was so engrossed in being the leading goalscorer. Not just at United but in the league, in the world, everywhere.'
If anyone doubts Scholes's version of events, here is Rio Ferdinand's take on how Van Nistelrooy would react after discovering that Henry had scored.
'He used to come in the changing room after a game, trust me, we're trying to win the league, we've beaten someone 3-1 or 4-1, he's scored one goal, he'll come in and look up to the TV [shake his head] and go "oh",' says Ferdinand.
'We'd ask Ruud what was wrong and he would reply "nothing, nothing". Then someone will go, "Thierry has scored two today, Ruud has only scored one, so he's a goal behind now". He's sitting there devastated, and you can see it.
'I used to think this guy is mad, we just won 3-1, he's scored a banger, set someone up as well, and he's disappointed!'
To appreciate the enmity between United and Arsenal at that time, consider this: these two rivals shared the Premier League title for no fewer than nine years in a row between 1996 and 2004 before Jose Mourinho's arrival at Chelsea ended the duopoly.
Henry signed for Arsenal in the summer of 1999 after United had overcome the Londoners in a titanic title race and that iconic FA Cup semi-final to win the Treble. In eight years with the Gunners, Henry won the Premier League twice and two FA Cups.
Van Nistelrooy joined United in 2001 and during five years at Old Trafford he lifted one title, the FA Cup and League Cup.
Significantly, however, Henry won the Golden Boot in four of those five seasons they went head to head, fuelling the Dutchman's insecurity and feelings of one-upmanship.
Van Nistelrooy scored 150 goals in all competitions and 95 in the Premier League. Henry hit 165 and 130 in the Premier League on the way to becoming Arsenal's all-time leading scorer with 228.
He was the winger-turned-striker who set the Premier League alight with a combination of pace, poise and penchant for wonderful goals.
Van Nistelrooy, meanwhile, was the classic penalty-box predator who offered a limited threat outside it but who was utterly deadly in front of goal. Two very different types of player with a single objective.
In Van Nistelrooy's first season at Old Trafford in 2001-02, he fired 36 goals to Henry's 31 but the Frenchman had the last laugh, scoring one more in the Premier League as Arsenal broke United's grip after winning a hat-trick of titles.
The following season he outgunned Henry with a record 44 goals in all competitions as United seized back their crown but lost to Arsenal in the FA Cup at Old Trafford in February 2003, a result that led to Ferguson kicking a boot into the face of David Beckham in the dressing-room.
The simmering tensions between the two clubs erupted during a bad-tempered clash at Highbury two months later when Sol Campbell was sent off for elbowing Ole Gunnar Solskjaer in the face. Henry scored twice and Van Nistelrooy once in a 2-2 draw.
It flared again in the Community Shield at the start of the 2003-04 campaign when Francis Jeffers was sent off and Campbell handed a retrospective three-match ban for lashing out at Eric Djemba-Djemba.
That was nothing compared to the scenes after Van Nistelrooy missed a last-minute penalty in a goalless draw during September 2003 in what became known as The Battle of Old Trafford. The Holland international was mobbed by Martin Keown and his Arsenal team-mates who went on to win the title and secure their place in history as the Invincibles. Henry outscored Van Nistelrooy by 39 goals to 30 and 30-20 in the league.
The mood wasn't helped in March 2004 when Van Nistelrooy's new strike partner Louis Saha was less than complimentary about his team-mate ahead of France's friendly international against Holland.
'Ruud lacks big-match experience,' said Saha, just days before United were due to face Arsenal in a FA Cup semi-final won by Paul Scholes's solitary strike. 'Thierry has played in major finals and he knows how to approach these games. Ruud doesn't take much part in collective play.'
Arsenal's 49-match unbeaten league run lasted until the following 2004-05 season when Van Nistelrooy made amends for his miss in the corresponding fixture by converting a disputed penalty in a 2-0 United win. But this clash descended into the Battle of the Buffet when Ferguson was hit by flying pizza after the match, thrown by Cesc Fabregas.
Wenger was subsequently fined £15,000 for branding Van Nistelrooy 'a cheat' while the United striker apologised to Ashley Cole for a reckless challenge that earned him a three-game ban. Ferguson weighed into the row by calling on the FA to take action against Henry for a tackle on Gabriel Heinze.
'There was one outstanding incident in the game with Arsenal which is worse than Van Nistelrooy,' said the United boss. 'The tackle on Heinze was terrible. You get the video, you watch that. What Henry did? That was bad.'
Having lost to United in the earlier rounds of the League Cup, Arsenal beat United on penalties in the FA Cup Final after a goalless draw. Van Nistelrooy endured an injury-hit season meaning that Henry won the Golden Boot by some margin with 25 league goals and 30 in total.
It didn't get any better for the Dutchman in his last season at United. He led Henry in the goal charts but fell behind after starting just one game in eight amid rumours of a growing rift with Ferguson.
After he was dropped for the final game of the season at home to Charlton, Van Nistelrooy left Old Trafford and didn't play for the club again.
With Henry beating him to the Golden Boot again, one can only imagine what he thought about being forced out of the team and denied the chance to compete with his great rival. Van Nistelrooy moved to Real Madrid and was joined in Spain by Henry a year later when the Arsenal man signed for Barcelona.
They both won two La Liga titles and the Spanish Super Cup but Henry also won the Champions League, UEFA Super Cup and Club World Cup under Pep Guardiola.
Who would have thought after all that that he could once have ended up at United? 'I saw Thierry Henry when he was playing for Monaco on several occasions but he was still very young, maybe only 17 or 18,' former United chief scout Les Kershaw revealed in 2002. 'He had phenomenal pace but he looked very raw.'
It could have worked out very differently for United and Arsenal, but then we would have been denied one of the great duels of the Premier league era.