Officials from several Premier League clubs were in attendance to see Moussa Diaby star in Bayer Leverkusen’s impressive Champions League win over Atletico Madrid in midweek, 90min understands.
Leverkusen, who many believed could mount a Bundesliga title challenge this season, have endured a terrible start to the new season.
They have won just one of their opening six league games, but Diaby has been Leverkusen's standout performer and he again was impressive in the Champions League.
Gerardo Seoane’s side turned on the style to beat Atletico Madrid 2-0, with Robert Andrich and later Diaby grabbing goals in the final ten minutes.
90min understands that Diaby's performance impressed a number of onlookers representing English clubs. Chelsea were one of the teams who were present, and it is understood they weren't there just to check in on loanee Callum Hudson-Odoi - who played on the opposite flank to Diaby - as the Frenchman is also on their radar.
While Diaby was at his best against Atletico, a return of one goal and two assists in nine games so far this season has seen him lose his place in Didier Deschamps' France squad for the September internationals.