Martin O'Neill admits his Sunderland side did not perform to a high enough level after suffering a 2-0 defeat at Blackburn on Tuesday night.
Chances were thin on the ground for the Black Cats as Rovers dominated for large chunks of the Ewood Park clash and O'Neill concedes their display was below par.
The manager was reminded of Sunderland's trip to West Brom late last month when they suffered a 4-0 thrashing after a woeful display.
He told Sky Sports: "We didn't play well enough, it's as simple as that. We didn't play well enough and we have to. We have to be stronger, obviously.
"Credit to Blackburn, they did fine, but we just didn't play well enough.
"We played poorly against West Bromwich Albion and there were shades of that tonight. I was expecting better obviously from all of us, including myself.
"If we're not up for the games, then we've got a problem."
Sunderland missed a glorious chance to equalise at 1-0 down when substitute Ji Dong-won blasted a shot over from close range.
O'Neill admits he sympathised with the South Korean, who had only been on the pitch for six minutes.
He added: "We missed that chance and I felt for him really, because he'd just got on the field of play. It's unfortunate."