In what was a largely one-sided affair, Chelsea dominated proceedings but fell to a 1-0 defeat, with a 74th minute finish by Rodrigo enough to hand Los Che all three points, leaving The Blues playing catch-up at this early stage of the tournament.
Ajax defeated French side Lille in the other game of Group H, and the defeat to Valencia means that Frank Lampard is still without a home victory from three games played at Stamford Bridge.
While some players like Fikayo Tomori and Willian impressed even in defeat, others failed to pull their weight and did not live up to expectation in the game against Valencia.
Here, we shall have a rundown of four players who were the most disappointing in the fixture against Los Che.
#4 Tammy Abraham
After starring in the Championship last season to help Aston Villa gain promotion back to the Premier League, it served as a no-brainer that he would return to his parent club Chelsea.
It was, however, a less than ideal start on his return for the 21-year-old as he missed the decisive spotkick in the Super Cup defeat to Liverpool. But in the last few weeks, he has risen from that early setback to become Chelsea's standout player of the season so far.
With seven goals, Tammy Abraham is the joint-highest goalscorer in the league. Given that he scored a hat-trick over the weekend, Chelsea fans would have been expecting him to transfer his red-hot streak to the Champions League.
However, that failed to happen, as the Anglo-Nigerian was largely on the peripheries of the game and was nothing more than a spectator in what was his Champions League debut.
This was not by no means his fault, as a congested Valencia midfield ensured he was devoid of quality service, but given his monstrous form, more was expected from Abraham.
He attempted just 12 passes all match long with a 75% accuracy, while he was bullied off the ball by Ezequiel Garay and Gabriel Paulista on the few occasions when he did get the ball in the Valencia box, with just one of his five shots in the game forcing a save from Cillessen.
It was a baptism of fire for the England International and Frank Lampard would hope he learns from this and returns to fire his side to glory.