Scarlets head coach Simon Easterby says his side did not turn up in the first half of their shock Pro12 17-13 derby defeat against 10th-placed Cardiff Blues at the Millennium Stadium.
Blues number eight Robin Copeland and Scarlets full-back Liam Williams were both sent off in Sunday's fiery encounter.
Easterby believes his side's slow start cost them dearly.
"The team were out on the pitch in body but probably not in mind," he said.
The Blues started the stronger with wing Alex Cuthbert crashing over near the corner to give them an early lead.
When Cuthbert jumped to take a high ball soon after, Williams took out his Wales team-mate in the air.
Easterby admits the Scarlets full-back, who was later sent off for a second yellow card offence, was lucky to escape with just the sin-bin for the challenge.
"Liam was lucky not to get a red card for that I think," he said.
"He's mistimed it and you just can't afford to take someone out in the air. Once they've left the floor they've got all the rights."
With Williams off the pitch, the Blues raced into an 11-0 lead.
Rhys Priestland scored a try to bring the Scarlets to within six points of the Blues before missing an easy conversion in front of the posts much to Easterby's frustration.
"I can't make an excuse for a guy to not kick that," Easterby said.
"I've not spoken to Rhys about it but I can imagine he will feel worse than anyone for having missed that."
Easterby's side hit back in the second half but were unable to overtake the Blues.
Scarlets knew that a win on Sunday would almost certainly have sealed sixth place and a spot in next season's European Cup.
Blues are now just a place behind their rivals, although they are unlikely to overhaul the nine-point gap in their two remaining fixtures.
"I think we are a far better team than we showed today and I am just frustrated and disappointed that we didn't show more positives in our game," said Easterby.
Cardiff Blues coach Paul John was delighted with the result.
"It's the first time in nine I think we've beaten the Scarlets so it's a great win for us," he said.
"The last five minutes were a bit tense for us but I'm just glad we managed to get the win."