Mike Phelan was at a loss to explain how Gaston Ramirez managed to score with a header on Monday night.
Phelan's Hull City lost 1-0 to Middlesbrough at the Riverside Stadium with former Tigers loanee Ramirez the man to steer home Viktor Fischer's corner on 60 minutes.
"Gaston is a talented individual who has settled really well at Middlesbrough but what really disappoints me is that Gaston has scored with a header because having known him that's not one of his fortes," Phelan said.
"It's disappointing because we had our set-piece jobs to do and we needed concentration and we lacked it at that moment in time.
"When it came to game certainly the possession wasn't in our favour but we had a few flash chances and but for a few incorrect decision-making moments we could have done better and possibly could have got a goal."