Chelsea interim manager Rafael Benitez says the European champions paid the price for mistakes made in the Capital One Cup semi-final first-leg clash as Swansea won 2-0 at Stamford Bridge.
Branislav Ivanovic was at fault for both goals, losing possession as Michu curled in the first before his backpass gifted Danny Graham the second.
Chelsea had plenty of chances to score but were wasteful near goal.
"We made two mistakes and paid for them," said Benitez.
While the defensive errors proved costly, Chelsea had 24 attempts at goal, compared with Swansea's five, but only eight of those were on target.
"We were doing a lot of good things but in football you have to take your chances," Benitez added.
"If we played this game 10 times, maybe we would win nine of them."
Benitez was unhappy that substitute Demba Ba had a goal ruled out in stoppage time for offside and that the Senegal striker was booked for an apparent dive in the penalty area.
"The goal was a goal - he was level," Benitez said.
"The penalty and yellow card, it wasn't a yellow card. The penalty depends on the decision of the referee."
Benitez refused to blame Serbian defender Ivanovic for the defeat.
"I can see any player making mistakes. It's not a big issue," he said.
"It's something that can happen, and the main thing is we have to carry on and try again.
"Obviously they have a great advantage but we have to go there, try to score a goal and we will be in the game."