Sold at £13m, then became £90m: Sunderland had a shocker over "world-class" titan - opinion

Sunderland have not been in the top-flight since they were relegated in the 2016/17 season as the Black Cats head towards the end of their fourth season in League One.

The Mackems went down five years ago after they scraped survival in the previous campaign under Sam Allardyce. The veteran boss came in to keep Sunderland in the top flight after Dick Advocaat was sacked in October 2015.

In the summer of 2015, the northeast side brought in the likes of Wahbi Khazri, Jeremain Lens, Younes Kaboul and Lamine Kone, among others, and they just about managed to do the job in the end, before going down the following year.

However, things may have been different had they been able to land one of their other targets in that transfer window – Virgil van Dijk from Celtic.

Advocaat wanted to bring the centre-back to the Stadium of Light and there was talk of a deal involving Steven Fletcher heading to Parkhead in exchange.

However, Southampton ended up completing a £13m swoop to sign the Dutch defender on 1 September, with his compatriot being unable to beat the Saints to the player’s signature.

In his first two seasons with the south coast club, Van Dijk averaged WhoScored ratings of 7.56 and 7.43 respectively as he consistently showcased his quality at the back. He took to the Premier League like a duck to water upon coming from the Scottish top flight, and his statistics show that he barely missed a beat.

His form caught the attention of Liverpool in the 2017/18 campaign and Jurgen Klopp moved to snap him up for a £75m fee – the most that had ever been paid for a centre-back at that time.

Since moving to Anfield, he has won the PFA Player of the Year award, the Premier League and the Champions League, whilst also being named in the