Valencia, who missed a glut of chances, had taken the lead through Carlos Soler.
Valencia: A freak goal from Valencia’s Daniel Wass earned the Spanish side a 2-2 draw in an epic encounter against England’s Chelsea on Wednesday that left both sides waiting to book their place in the Champions League’s knockout stage.
Valencia, who missed a glut of chances, had taken the lead through Carlos Soler but goals from Mateo Kovacic and Christian Pulisic flipped the match on its head.
The Spaniards missed a penalty through Dani Parejo, but drew level late on when Wass netted a remarkable effort, shaping to centre before finding the net with a finish across goal.
The draw means both sides are on eight points after five games but Valencia have a better head-to-head record and so are second in Group H, with Chelsea in third.
Ajax Amsterdam sit top on 10 points after winning 2-0 at Lille, who are bottom with one.
Valencia visit last season’s semi-finalists Ajax in their final group game and will have to win there to ensure they qualify, while Chelsea will book their place in the last-16 if they beat Lille at home.
“We nearly won it, nearly lost it. It was end to end, not that we wanted it to be,” Chelsea boss Frank Lampard said.
Valencia coach Albert Celades added: “The sensation in our dressing room is that we have missed a very good chance to qualify for the next round. But to get to the last game with our fate in our hands is not bad.”
Victory for either side at Mestalla would have sent them through and Valencia went ahead when Soler scored in the 40th minute after team mate Maxi Gomez had missed two gilt-edged opportunities.
Yet Kovacic levelled for Chelsea two minutes later, netting for the first time in 122 club games.
Chelsea’s top scorer Tammy Abraham was carried off on a stretcher with a serious-looking injury before halftime, although Lampard said after the game the striker had only suffered a knock to the hip.
Valencia defender Jose Gaya was also taken off on a stretcher after fulltime having collapsed on the pitch.
United States international Pulisic put Lampard’s side ahead in the 50th minute after a lengthy VAR review ruled him onside.
Valencia forward Rodrigo Moreno missed an open goal later in the half and then the home side were awarded a penalty.
But captain Parejo was denied from the spot by Chelsea keeper Kepa Arrizabalaga, spurning a second penalty in the competition after also missing in the defeat to Ajax Amsterdam.
The Spaniards eventually levelled in the 82nd minute with a remarkable goal from Danish midfielder Wass, who looked set to cross from the right wing but instead flummoxed Arrizabalaga by firing a shot across goal which bounced off the far post and into the net.
Valencia should have won the game in added time but Rodrigo failed to connect properly with a cross from close range, while Chelsea had a shot cleared off the line before then and Valencia keeper Jasper Cillessen denied Michy Batshuayi.
“Parts of our performance I’m not mad on. We gave away too many chances. We missed a lot as well,” said Lampard.
“They were arriving in our box too much. Credit to the players for their work-rate and hanging on in there, but sometimes you have to be more secure than that.”
Valencia defender Ezequiel Garay added: “We had a lot of chances and we deserved to win but we have to believe we can win and go through in Amsterdam.”