Title contenders often follow a golden rule in the transfer market: don’t sell to direct rivals.
However, there are a fair few occasions where this rule hasn’t been followed. Sometimes the player wanted to leave; other times the club received an offer they couldn’t refuse.
Some of these players went on to be superstars at their new clubs, bringing in almost instant success. Others were…well…a bit rubbish.
In no particular order – here we go:
Carlos Tevez (Manchester United to Manchester City, £25m)
1/2 OTD in 2009 Carlos Tevez signed for Manchester City. This 'Welcome' poster soon appeared close to Manchester's city border on Deansgate- pic.twitter.com/rTPWEmDsNO
— Dr Gary James (@GaryJamesWriter) July 13, 2017
After winning two titles and a Champions League at Manchester United, Carlos Tevez was widely expected to make his loan deal permanent at Old Trafford.
However, he decided not to stay on at the Red Devils and instead moved to rivals Man City, where he was welcomed by a controversial “Welcome to Manchester” billboard.
The Argentine helped Man City achieve great things, winning the FA Cup in 2011 – their first piece of major silverware since 1976. And, just a season later, he helped the Cityzens pip his former club to the Premier League title on goal difference.
Sol Campbell (Tottenham Hotspur to Arsenal, free)
Moving from Tottenham Hotspur to Arsenal won’t exactly make you the most popular figure, but it proved to be the right move for Sol Campbell.
Having finished ten points behind Man Utd in the previous year, Campbell’s arrival propelled the Gunners to the top of the table in the following season, finishing seven points clear of Liverpool in second place.
The England international later became an Arsenal legend, being a crucial part of their ‘Invincibles’ team of 03/04, as well as scoring in a Champions League final.
Juan Sebastian Veron (Manchester United to Chelsea, £15m)
Having established himself as one of the world’s finest midfielders in Italy, Lazio midfielder Juan Sebastian Veron made a British record move to Man Utd. Things didn’t go to plan, and he was sold to Chelsea two seasons later for almost half of his original fee.
Did he rediscover his best form at Stamford Bridge? Well…no is the answer.
The Argentine made just 14 appearances for the Blues in all competitions, spending three years out on loan before returning to Estudiantes.
Eric Cantona (Leeds United to Manchester United, £1.2m)
Cantona was a controversial figure in France but had undeniable talent, which he proved at Leeds United. During his brief stint at Elland Road, he won a First Division title, and scored a hat-trick in a Charity Shield game against Liverpool.
Sitting in eighth place at the time, Sir Alex Ferguson came calling for Cantona’s services, following a fall out with Leeds manager Howard Wilkinson. The Frenchman soon arrived at Old Trafford, and was an instant hit, helping the club to the title in his first few months.
But his success didn’t stop there. Cantona played five seasons at Man Utd, winning four Premier League titles – missing out on the other one due to a lengthy ban.
Raheem Sterling (Liverpool to Manchester City, £49m)
Raheem Sterling garnered a lot of attention as a teenager at Liverpool, starring as they came second in 2013/14. Not long after, he made the switch to Man City.
It took time for the winger to make his mark at the Etihad, generally struggling until the arrival of Pep Guardiola. But once the Catalan took over at Man City, Sterling managed to reach his full potential.
The 26-year-old has won six domestic honours at Man City and is on course for more this season.
Fernando Torres (Liverpool to Chelsea, £50m)
While Sterling left Anfield and achieved great things, Fernando Torres proved that the grass isn’t always greener.
After suffering from injuries in his final days at Liverpool, Chelsea splashed out £50m for Torres on transfer deadline day January 2011. It was a complete disaster.
The early signs weren’t encouraging, with the Spaniard netting just once in his opening six months at the Londoners. Things didn’t get much better in the following season, scoring 11 in 49 in all competitions.
The Blues managed to get some form out of him at times, but it was clear that his best days were over.
Nonetheless, his time at Stamford Bridge wasn’t all bad. After all, his equaliser against Barcelona during Chelsea’s Champions League triumph will never be forgotten.
Robin van Persie (Arsenal to Manchester United, £24m)
In the midst of Arsenal’s infamous trophy drought, Robin van Persie decided to seek success elsewhere. Being one of the world’s best forwards, there was no lack of interest in him. This made his decision to join bitter rivals Man Utd only more difficult to take for Gunners fans.
Despite this, it brought instant success. After missing out on the title the season before, Sir Alex Ferguson’s men reclaimed the crown in 2012/13 by a resounding 11 points.
Furthermore, Van Persie was essential, winning a second successive Golden Boot with 26 goals.
Andy Cole (Newcastle United to Manchester United, £7m)
In his first-ever Premier League season, then-youngster Andy Cole dazzled in the top flight, winning the Golden Boot with 34 strikes at Newcastle.
Six months later, he was sold to Man Utd, where he became part of an enormously successful side.
The striker would punish his former club in the 1995/96 campaign, as his new side narrowly won the title over Newcastle. In that same season, Cole netted the opener in a 2-0 win over his former employers.
Kevin Keegan’s men wouldn’t have missed Cole too much – Les Ferdinand had come in from QPR and filled the void without any problems. However, it will have hurt knowing that they may have got their hands on the league title had he been sold elsewhere.
Alexis Sanchez (Arsenal to Manchester United, swap deal)
Not every Man Utd signing on this list has been positive.
With six months left on his contract, Arsenal star man Alexis Sanchez transferred to Man Utd in a swap deal with Armenian playmaker Henrikh Mkhitaryan. Who benefited most from the deal? Their agents, probably.
Neither player was a massive success. Mkhitaryan showed the occasional flash of promise, but never consistently produced for the Gunners, and later departed for Roma on a free transfer.
Meanwhile, Sanchez never came close to replicating his best form at Old Trafford, scoring just five goals in 45 outings in all competitions. Like Mkhitaryan, the Chilean also left on a free transfer and is currently plying his trade with Inter Milan.
N’Golo Kante (Leicester City to Chelsea, £32m)
After helping Leicester to a miraculous title win against all odds, N’Golo Kante earned himself a move to Chelsea, who had finished tenth the season before.
The next season proved just how important he was. The Foxes went from champions to relegation candidates, while the Blues shot up from mid-table to title winners. Kante won PFA Player of the Year for his outstanding performances.
Since then, the little Frenchman has won an FA Cup and a Europa League at Chelsea, as well as a World Cup with his country.