Chelsea boss Frank Lampard has admitted that star striker Timo Werner did not take a penalty in the shootout defeat by Tottenham because he had cramp.
Werner has impressed since his summer arrival from RB Leipzig and was expected to be one of the Blues' first five penalty takers on Tuesday night.
Instead, the German was nowhere to be seen and Lampard explained after the game that he refused the chance to step up to the spot because of the cramp.
'We spoke to the players,' said Lampard afterwards. 'You work on penalties and try and have a plan but it's very difficult to know.
'Timo had some cramp at the end and Timo would have probably taken one so we had to adjust around that.'
Werner suffering from cramp might be somewhat of a surprise given that he had played only 90 minutes - there was no extra-time in the game, which went straight to penalties after the stalemate.
Chelsea's players also had an extra day to recover from their previous match - a 3-3 draw at West Bromwich Albion on Saturday - than Tottenham's players, who drew 1-1 with Newcastle on Sunday.
In the shootout, all of the first nine penalties were scored, with Eric Dier, Tammy Abraham, Erik Lamela, Cesar Azpilicueta, Pierre-Emile Hojbjerg, Jorginho, Lucas Moura, Emerson and Harry Kane all successfully finding the net.
Then, much to Blues fans' surprise, rather than Werner it was Mason Mount who stepped up for the decisive kick, but he could only find the outside of the post and Chelsea were knocked out.
Mount's missed spot-kick means Tottenham go through to the quarter-final of the Carabao Cup, and they will find out their opponents for the next stage of the competition on Thursday.
Jose Mourinho's side now have less than 48 hours' rest before their home Europa League play-off clash with Maccabi Haifa.