When Tottenham sold Dimitar Berbatov to Manchester United in 2008 it was in the most begrudging of circumstances. After a summer of haggling, a player on strike - the forward eventually forced his £30 million move on deadline day, leaving a Spurs side behind him who were winless in the league and boss Juande Ramos veering towards the sack.
This summer when United came enquiring after Luka Modric they were given short shrift - Tottenham were resolved to reluctantly sell, but only to a club abroad.
The deal was one of Spurs chairman Daniel Levy's crowning achievements, from a business perspective at least - securing £33 million for the Croatian was an excellent price, even if it did take longer than had hoped and overshadowed Spurs' season preparations.
In the midst of all this, Tottenham had been attempting to sign Zeki Fryers from Manchester United whose contract was running down. As he is just 20, under Premier League rules United would have been entitled to compensation, of up to £6 million which Spurs did not wish to pay or pursue down the complex legal channels.
So Fryers ended up in Belgium, making a surprise move to Standard Liege. He was off radar until last week when he clinched a move to Spurs.
Sir Alex Ferguson was quick to accuse Tottenham of wrongdoing, saying they had somehow conspired to exploit the system, calling for an FA investigation to even go as far as searching the North London club's e-mails and phone records, describing it as a 'typical Daniel Levy deal'.
Spurs were quick to hit back, claiming they were as surprised as United were when Fryers went to Belgium, but took advantage of a manager change at Liege and Fryers losing his place in the team to try and tempt him back to the Lane in January; they were of course successful and there was no compensation to pay to United, simply a transfer fee to Liege for an amount which remains undisclosed.
Whichever the truth, the general perception is that United have lost out, and Spurs have worked the system to their advantage, and the league leaders certainly have a bitter taste in their mouth.
But that can all change if reports coming out of Spain are to be believed, which are that United are considering attempting to lure Luka Modric to Old Trafford.
The smile on Daniel Levy's face will quickly be wiped from it if Luka Modric rocks up at White Hart Lane in a Red Devils shirt next season.
The Croatian has so far failed to shine at Madrid, being voted the biggest flop of the season by Marca readers, and while he is expected to stick it out until the summer, a solid offer from United could tempt him.
After the way Levy made it difficult for United to negotiate for Modric, blankly refusing their enquiry, it would be an ideal response for Sir Alex Ferguson to seal a deal for Modric, especially considering they would be unlikely to pay as much as Madrid did this summer for his services.
How would Spurs fans feel if Modric ended up at United?
image: © Ronnie Macdonald