After narrowly avoiding relegation last season, Tottenham has decided to draw a line: Pedro Porro is not for sale, despite interest from Manchester City and Real Madrid. According to reports, the club will do "everything it can" to keep the Portuguese full-back - a phrasing that, in negotiating language, usually means a price exists, it's just very high.

And it's not hard to understand why. In a season that ended in 17th place - a disgrace for a club with Tottenham's ambitions - Porro was among the few who consistently played at a high level. 47 appearances in all competitions, two goals and six assists from a full-back position. When the whole team sinks, the one who swims gets noticed.

Under Roberto De Zerbi, Porro's role has grown tactically too. In attack he tucks into the middle to build the play and break the opponent's press, while João Palhinha drops into his place in defence. The moment the ball is lost, Porro drops back. This isn't an ordinary full-back; this is a player you build a system around.

Real Madrid have already shifted their gaze to Inter's Denzel Dumfries, and Manchester City are looking at Newcastle's Tino Livramento - a sign that both clubs realise Tottenham won't give in easily. Losing Porro would be a double blow for the Londoners: hard and expensive to replace, and the money spent there is money that won't go to the other holes in the squad. Sometimes the best signing is the one you won't sell.