"He's awesome," the stud receiver says ... "We love him. We love him. It's been fun."
Of course, there are a few dudes in Pittsburgh who'd disagree ... Brown left the Steelers on bad terms a few months ago -- and everyone from JuJu Smith-Schuster to ex-teammate Ryan Clark blasted the guy.
But, it's so far, so good in Oakland ... so says Tyrell (who just signed with the Raiders this offseason himself), 'cause the WR tells us he's actually learning some tricks from Brown.
BTW, we also spoke with Tyrell about the Raiders' future move to Vegas ... and he says he's got no worries about the future trek to Nevada!