FRANK LAMPARD’S Chelsea were undone by an opportunistic Valencia side in this Champions League clash at Stamford Bridge.

The Group H opener was settled when Rodrigo fired the Spanish side ahead in the 74th minute.

Chelsea substitute Ross Barkley had an opportunity to level with three minutes of the match remaining. However, he slammed his penalty kick against the crossbar.

“It was a harsh lesson in Champions League football – a game we played well in and we lose it,” said Lampard, in his first Champions League match as Chelsea boss. “The good news is we have five games left in the group.”

Chelsea’s future in the competition, however, is now in jeopardy as they need vital points when they visit Lille on 2 October and Ajax on 23 October.

Chelsea had been dealt an early blow when young midfielder Mason Mount was substituted after sustaining an injury.

“We don’t know how bad it is,” said Lampard. “We are going to have to assess it in the next 24 to 48 hours to see the scale of the injury. It’s too soon to say. Obviously, it was a shame because he was playing so well and started well.”

Valencia, mid-table in the Primera Liga after an uneven start to their league campaign and in turmoil behind the scenes, had their fair share of possession in an enjoyable first half.

Lampard’s men, however, responded positively and it appeared that it would be only a matter of time before they would find the breakthrough.

Striker Tammy Abraham had an opportunity to open the scoring on 26 minutes, but his glancing header flew wide of Jasper Cillessen’s goal.

Moments later, Kevin Gameiro raced onto a clever chipped pass from former Arsenal player Francis Coquelin. The Valencia striker collected the ball, but defender Fikayo Tomori was alert enough to see off the danger.

The home side began the second half slowly. Gameiro had a great chance to open the scoring after a clever corner kick routine surprised the Chelsea back line.

Chelsea were less positive after the interval, and when Valencia’s Rodrigo toe poked the ball beyond Kepa Arrizabalaga from close range, the home faithful fell silent.

Chelsea were awarded a spot-kick after a VAR decision ruled that defender Daniel Wass had handled the ball.

Barkley was seen to forcefully made his point to Willian and Jorginho that he would be taking the penalty with a suggestion that he may have gone against the pre-designated order of kick takers.

Moments later, he struck his effort all too high, hitting the woodwork.

Lampard said: “Ross is the penalty taker. He was in pre-season and scored a couple. He has been when he started. He was when he came on and he missed it.

“That is the clear story. I don’t know what the conversation was, but Jorginho and Willian were the takers on the pitch. When Ross comes on he becomes the penalty taker.”