Hibernian manager Colin Calderwood felt mistakes from his players and the match officials were the only difference between his side and Motherwell after another defeat further embroiled the Edinburgh side in relegation trouble.
Headed goals from Jamie Murphy and Steven Saunders midway through the first half at Fir Park earned Motherwell a 2-0 victory as Hibs failed to bounce back from their Scottish Cup defeat by Ayr.
The Hibs boss, who has now won just two of 15 games in charge, said: "I'm frustrated because there were bits of that game that were good for us. What was pleasing was the application from 2-0 down. We then created one or two very good opportunities but the team that made the least mistakes has won the game. There is nothing else the winning team has done better than us."
Graeme Smith let Murphy's header bounce over his hand in the 20th minute but Calderwood felt several home players were offside when Stevie Hammell swung in the free-kick.
Saunders soon headed home Hammell's corner and Hibs threw away a lifeline in the 44th minute when Merouane Zemmama missed a penalty. However, Calderwood felt referee Alan Muir should have played the advantage after the handball from Saunders.
Calderwood, who restricted Derek Riordan to a substitute's appearance as the striker battles a hip complaint, said: "The ball shouldn't have gone in for the first one but they're offside. The second one was our fault entirely.
"But when the rules are contravened, because they are offside when the kick is taken, that might be the stroke of luck we need."