Manager Jos Luhukay refused to criticise captain Tom Lees despite his costly mistake in Sheffield Wednesday's defeat to Middlesbrough.
Lees, a linchpin of the Owls' defence in recent years, was at fault for Boro's second goal.
Midfielder Mo Besic, who had earlier fired Boro in front, pounced on Lees' poor back pass before calmly squaring the ball to Britt Assombalonga, who kept his cool to slot home his fifth goal of the season.
Former Boro man Adam Reach gave Wednesday a lifeline in the 82nd minute with a fine right foot volley but the visitors held their nerve to return to the top of the Championship.
Luhukay told The Star: "Tom was very, very disappointed after the game but he is our captain. He is a fantastic character and a good defender.
"Sometimes these things happen. We must look forward.
"It is important that we help give support to the the players who made the mistakes and hopefully it won't happen again.
"Nobody means to make mistakes. We must support our players and help them for the next game."
Reach twice came close to putting the Owls ahead in a tight, evenly-balanced first half.
Luhukay, who accepts Wednesday were "not strong enough or good enough" to put Boro to the sword, bemoaned their lack of ruthlessness in the final third, saying: "We had the first half completely under control. Middlesbrough had no chances and and we had two or three to score but we didn't.
"When you play against a top team in the Championship, you must take your chances.
"We gave two goals easily away in the second half and Middlesbrough profited from our defensive mistakes. It was then difficult to come back as Middlesbrough don't give a lot of goals away.
"They are strong defensively as a team team but we made it 2-1 and in the last minutes of the game we nearly made it 2-2.
"It was what we expected. It was a very difficult, tough game with a high intensity."