Frank Lampard's first Champions League match as Chelsea manager ended in defeat on Tuesday as Ross Barkley missed a late penalty in a 1-0 home loss to Valencia.
Rodrigo put the visitors ahead 16 minutes from time before the hosts won a debatable spot-kick after Daniel Wass was adjudged to have handled in the box.
But substitute Barkley smashed his penalty against the crossbar to spurn the opportunity to rescue a last-gasp draw.
The Blues suffered an early blow when academy graduate midfielder Mason Mount sustained an injury just nine minutes into the match and had to go off.
The 20-year-old suffered a strong blow to his ankle after a challenge from former Arsenal midfielder Francis Coquelin, who was shown a yellow card.
In Pictures | Champions League: Chelsea v Valencia | 17.09.19
Mount initially tried to carry on but soon realised he could not run it off and departed to applause at Stamford Bridge.
