West Ham fans are saying “I told you so” after Brentford supporters turned on El Hadji Malick Diouf following his costly performance in the 3-2 Carabao Cup defeat to Sunderland.

Senegal international El Hadji Malick Diouf joined the Bees from West Ham in August in a deal worth up to £40m, with the Hammers banking a substantial profit on a player whose departure had become increasingly acrimonious.

Now Brentford supporters are questioning whether their club made a serious mistake, with the left-back coming in for fierce criticism after a difficult evening at the Stadium of Light.

And back in east London, plenty of West Ham fans will feel their warnings have been vindicated.

Brentford fans turn on £40m West Ham signing

Brentford were knocked out of the Carabao Cup on Wednesday after Sunderland scored three times in a devastating first-half spell before the Bees mounted a late fightback.

Diouf endured a particularly uncomfortable evening defensively. He was beaten by Jocelin Ta Bi in the build-up to Sunderland’s second goal, with the winger getting past him before pulling the ball back for Timur Tutierov to score.

The performance added fuel to growing concerns among Brentford supporters about the £40m signing, with fan reaction following the defeat focusing on his defensive errors and whether his performances justify the fee.

The criticism is particularly striking given that Diouf was signed as a long-term investment, having impressed enough at West Ham to attract Brentford’s interest at just 21 years old.

The reported deal involved an initial £35m fee plus £5m in add-ons, making it a major outlay for the Bees, who rarely make recruitment mistakes.

Until now it seems, with many Brentford fans turning on Diouf and labelling him the biggest waste of money in the club’s previously modest history of recruitment.

“West Ham had our eyes out with Diouf,” one Brentford fan said on X.

“Diouf is awful, West Ham must be laughing at us.” another Bees supporter commented.

Another Brentford supporter questioned why the club even signed Diouf in the first place, let alone for £40m.

“We really saw Keane Lewis-Potter look exceptional at left back, have Hickey as a great back-up option with Meghoma a brilliant talent coming through. And then decided it was the smart move to spend £40 million on a left back who can’t defend,” the Bees fan said.

“Don’t want to see Diouf or Valdimarson in a Brentford shirt for a very long time,” another Brentford fan said.

The former Hammer was ‘defensively all over the place’ according to another Brentford fan on X, who said: “Diouf might be the worst £40 million we’ve ever spent. West Ham have pulled our pants down, defensively all over the place.”

One Bees supporter went as far as to state Diouf will make history at his club for all the wrong reasons, saying: “Diouf will go down as the worst signing in our history.”

West Ham fans warned Brentford about Diouf

The reaction will be familiar to West Ham supporters, many of whom questioned Diouf’s £40m valuation when Brentford’s interest emerged during the summer.

Those doubts were compounded by the circumstances surrounding his exit.

Diouf was widely reported to have downed tools in an effort to force a move to Brentford, with concerns about his commitment prompting West Ham to leave him out of matchday squads.

He also angered supporters by liking a social media post announcing West Ham’s defeat to Charlton Athletic while he was absent from the squad.

The manner of his departure meant there was little sympathy for the defender among sections of the Hammers fanbase, particularly given the club’s need to rebuild after relegation.

West Ham ultimately agreed to sell Diouf for a fee that could reach £40m, having signed him from Slavia Prague for a reported £19m the previous summer.

That represents the potential for a substantial profit on a player whose performances had divided opinion during his time in east London.

Koppen’s £40m Diouf deal looks like a masterstroke

There is still plenty of time for Diouf to develop, and one difficult cup performance does not settle the debate over his long-term value.

Brentford signed him because of his age, potential and attacking qualities, and the club will hope he can improve as he adapts to a new environment.

But the early criticism has handed West Ham fans an opportunity to remind their London rivals that they were never entirely convinced by the deal.

For Nils Koppen, the sale looks like a useful piece of business. Whether Brentford eventually feel they have spent their money wisely remains to be seen.