Chelsea had the chance to cancel out Rodrigo’s 74th-minute opener and salvage a point when the Video Assistant Referee alerted the on-field official to Daniel Wass’ handball in the area with three minutes remaining.
Barkley insisted he should take the spot-kick, snatching the ball off regular penalty taker Jorginho, but his effort cannoned off the top of the crossbar.
Valencia players and fans supposedly arrived in London in disarray following the sacking of manager Marcelino last week, but they were far from mutiny as they produced a classy display against Lampard’s youthful side which featured four competition debutants.
Tammy Abraham, fresh from his hat-trick at Wolves, was denied a maiden Champions League goal when his near-post flick was blocked by Valencia goalkeeper Jasper Cillessen.
Mason Mount then received a painful introduction to Europe when former Arsenal midfielder Frances Coquelin left his studs on the inside of the youngster’s shin which yielded only a yellow card and forced the youngster off inside 16 minutes.
Abraham went close again with a far-post header from Cesar Azpilicueta’s cross and Willian’s powerful run through the middle only produced a shot which flew wide.
Willian, Chelsea’s biggest threat in the first half, almost fashioned a spectacular opener when he controlled Mateo Kovacic’s cross-field pass on his chest, but his first-time shot flew over. And on the stroke of half-time the Brazilian’s fierce drive towards the near post was parried clear by Cillessen.
Marcos Alonso took the game to Valencia early in the second half, drilling in a free-kick which Cillessen tipped behind before heading the resulting corner over.
But in the 74th minute, they fell behind, Rodrigo giving the Chelsea defence the slip as he raced onto Daniel Parejo’s chipped free-kick and swept the ball past Kepa Arrizabalaga.
The drama reached fever pitch five minutes from time when Chelsea’s players appealed for a handball, and replays did indeed show Fikayo Tomori’s header had struck the hand of defender Wass.
After an interminable VAR delay, a spot-kick was finally given but Barkley, on as a substitute just seven minutes earlier, took responsibility into his own hands only to crash his effort against the frame of the goal.