Manager Derek Adams is demanding better from his central defenders after Ross County lost 3-1 at Motherwell.
Melvin De Leeuw gave County the lead at Fir Park but the Steelmen replied three times in the second period.
"We were still in control of the game but we haven't dealt well with two balls into the box," lamented Adams.
"One was from a corner kick, one from another cross - and another from a ball in behind. That's how they got their three goals."
Scott Boyd and Grant Munro were paired in the heart of the Staggies' defence, the latter a 37th-minute replacement for Brian McLean, who took a head knock.
But their defensive line was breached twice by John Sutton and once by Bob McHugh as Motherwell consigned County to their fifth league defeat in eight games.
"I thought all in all we played very well today but we really have to defend the cross ball better. I don't think we deserved to lose the match 3-1," Adams told BBC Scotland.
"The two centre-halfs know that they are at fault for the three goals and we have already spoken about that.
"I thought we played very well in the first half. Motherwell didn't really trouble us. We created some good openings and we scored a goal from Melvin De Leeuw.
"It's been the story of our season so far where we've had good opportunities in the match and then the other team have taken an opportunity.
"I think that was the case in the second half, We got into their 18-yard box a number of times and their goalkeeper has had to make a number of good saves."