Arsenal boss Mikel Arteta admits he has an insider at today's opponents Leeds United.
Arteta is set to be without new £40million midfielder Thomas Partey.
And both Sead Kolasinac and Mohamed Elneny are missing after contracting coronavirus.
But Arteta has the inside track on spymaster Marcelo Bielsa from a secret source.
He said: “One of my best friends spent many, many years with him.
“Who is it? I prefer not to say, but they worked as a player and then next to him.
“So I know a lot about his methods, who he is as a person, who he is as a manager as well and I've admired him for many, many years.
“I've been very impressed with what he has done in England since he joined Leeds.
“He has transformed the club. He has transformed the belief of everyone around the club, the fans, that they could come back and be the club they were a few years back."