Scotland coach Matt Williams could not disguise his anger after his side were thumped 46-22 by Wales at Murrayfield.
Although Scotland were competitive in the second half they were never likely to claim victory after going in at the break 38-3 behind.
"I was disgusted with the first half," he said. "I was fuming and embarrassed by our defensive display.
"We just missed tackle after tackle, or were not there to make the tackles, and it was totally unacceptable."
Scotland were abject before the break as Wales ran in five tries in a scintillating display.
And Williams said the way his side responded after the interval did not erase the faults of the first half.
"We were very poor in the first half," he added. "We were much better after the break but that makes it even more infuriating because it means we can do it.
"We did stand up in the second half, we did run the ball, we did play attractive rugby, we didn't kick aimlessly, we did counter attack and we did get in their faces but we didn't do it for 80 minutes.
"We won second half and Wales probably took their foot of the pedal but we cannot possibly play in that second half and hold our head up with any pride about what we did in the first half.
"Wales are the best side we have played and you have to give them credit. I don't wish to take away from their deserved win but we made it easy for them."
Williams went on to reiterate that he is going to stick it out with Scotland and demanded to see a better performance against England next weekend.
"It's a great honour and a privilege to be in charge of Scotland and I knew exactly what I was taking on," he added.
"Some parts of the job are so uplifting but that first half display was a real smack in the teeth.
"However, I will never walk away from this job.
"I'm going to kick that many backsides so hard and so often this week, the players will know we can't have another display like that.
"We have to play for 80 minutes against England and build on what we did well in the second half.
"We can't afford to drop our heads like we did out there and like we did against Ireland when things go against us."