Mohamed Diame admitted Rafa Benitez had every right to be upset with his Newcastle United players.
The club’s six-game winning run came to an end on Saturday.
Wolverhampton Wanderers won 2-0 thanks to an own goal from Chancel Mbemba and a strike from Helder Costa.
Newcastle – who had beaten Queens Park Rangers 6-0 four days earlier – started badly at St James’s Park.
And Wolves took advantage of an error-strewn performance to claim three points.
Diame, recalled to the starting XI after sitting out the QPR win, was at a loss to explain what happened against Walter Zenga’s side.
Asked what went wrong, the 29-year-old said: “To be honest, I don’t know.
“But we are all really disappointed. It was an important game for us, because we were at home and we have just had a great result away.
“It was important to confirm that result, but we didn’t and we have to make sure we don’t lose the confidence we had because we know we have got a quality squad so we just need to come back, work hard and be ready for the next match.”
Benitez bemoaned his team’s sloppy start after the game.
“Early on we felt something wasn’t right in our play,” said Diame, signed from Hull City this summer for £4.5million.
“Normally we always get the possession and provide a good tempo in the game, but against Wolves, we were playing the wrong way for whatever reason.”
Jon Dadi Bodvarsson and midfielder Costa were simply too hot to handle and with Newcastle, who had Vurnon Anita sent off for a late challenge on substitute Ivan Cavaleiro, drastically under-performing all over the pitch, the visitors were good value for the points.
Wolves went ahead when Mbemba headed Bodvarsson’s driven cross into his own net.
Then in the second half, Costa was allowed time and space to curl a left-foot effort across Matz Sels and inside the far post.
It might have been worse for Newcastle had Bodvarsson not cleared the crossbar with a shot on the turn with 19 minutes remaining, but it was bad enough when
Anita was sent off for a late challenge on Cavaleiro – though the challenge was nowhere near as bad as Diame’s high challenge on Matt Doherty in the first half.
Newcastle: Sels, Anita, Mbemba, Lascelles, Dummett, Ritchie (Atsu 63), Shelvey, Hayden (Mitrovic 63), Perez , Diame, Gayle. Subs Not Used: Clark, Colback, Gouffran, Yedlin, Darlow. Sent Off: Anita (87). Booked: Dummett, Diame, Ritchie.
Wolverhampton: Ikeme, Doherty, Iorfa, Batth, Borthwick-Jackson, Edwards, Saiss, Oniangue, Helder Costa (Mason 75), Bodvarsson (Coady 88), Joao Teixeira (Ivan Cavaleiro 71). Subs Not Used: Gladon, Saville, Lonergan, Hause. Booked: Batth, Saiss, Joao Teixeira, Borthwick-Jackson, Edwards. Goals: Mbemba 29 og, Helder Costa 62.
Att: 52,117 Ref: Tim Robinson (West Sussex).