Chris Wilder acknowledged his side had missed a big opportunity to register a fifth straight league win, following defeat against Swansea City in Wales.
Oli McBurnie's second-half strike settled the contest in the favour of the Swans at the Liberty Stadium, but Wilder was left ruing missed opportunities in the first 45 minutes.
He remarked: "I've said to the players, all these Championship games are really tight, usually they are 50/50 or 55/45, that's not been a tight game.
"A negative was our start to the second-half, we turned possession over too easy, but we should be 2-0 up at half-time.
"They found that bit of quality to win the game, a give and go and McBurnie scores, but we got in that position a dozen times and haven't found that final pass, they did.
"We kept going and kept going, the attitude was great, it's just that bit of quality, we changed our shape and went for it and I'm happy that if we lose a game we go out of the front door.
"But that's another game, out of the eight defeats, taking the Middlesbrough game out of it, that we've been in and that's not through rose tinted glasses.
Wilder continued: "No disrespect to Swansea, but the result was lost in our changing room, but maybe not won in theirs.
"This was never going to be an easy game, one where we just turned up and rolled these over, but for me it wasn't a close game,
"We've lost a game through not being clinical enough, we shouldn't have been chasing the game, we should have been seeing it out."