Daniel Farke felt Leeds United fell victim to some "crazy" decisions as they were beaten 1-0 by Sunderland at Elland Road.
The Black Cats emerged victorious after Habib Diarra converted a 70th-minute penalty with their only shot on target in the game.
Ethan Ampadu was judged to have handled when Wilson Isidor's shot spooned in the air, while the Whites also saw Pascal Struijk denied a spot-kick after being grappled by Luke O'Nien in the first half.
It added to the hosts' frustration, with Leeds having 18 shots to Sunderland's three, more touches in the opposition box (25 to nine), and more final-third entries (65 to 39).
Farke was at a loss to explain how his team ended up on the losing side.
"It's difficult and tough to take. It's football sometimes. We were so dominant. We knew we would face a very compact side. They're difficult to open up," he said.
"We had so many set-pieces and didn't give one chance away and still lost. We lacked clarity in the final third. There were some crazy decisions for the penalty (that was not awarded) with Struijk.
"Sometimes it's written in the stars. With Ampadu, it was instinctive and he gives a penalty away.
"The difficult thing to explain is how the penalty went in. We have to be more brutal in front of goal. I'm happy with many topics and the mentality. We didn't show quality to score – so it's very frustrating."
Sunderland's victory means they have now reached the fabled 40-point tally, a number long suggested as the target to reach to avoid relegation.
They have done so with nine games to spare and boss Regis Le Bris spoke about how they must now adjust their aspirations.
"It's important," the Frenchman told TNT Sports.
"It was key, we don't know if it will be enough but it's a good target, with nine more games to play we want to stay ambitious, the next target is 43!
"We also have the FA Cup, which is an objective for us too."
This was just the fifth game in the Premier League this season to see a team win via just one shot on target, with Sunderland accounting for two of those (also v Newcastle United in December).