Liverpool manager Jurgen Klopp was unhappy that Chelsea's equalising goal was not ruled out for offside in the Blues' 2-1 win at Anfield in the Carabao Cup on Wednesday.
It was a very tight call for referee Kevin Friend. Two Chelsea players were standing in offside positions when the free kick came in but neither interfered with play. Ross Barkley, who headed the ball, may have been offside as well by a matter of inches.
Emerson poked in the rebound and despite VAR being in operation, Friend was not instructed to check for a possible offside. Eden Hazard scored the winning goal minutes later while Klopp was left to rue that crucial turning point.
"We knew how Chelsea wanted to play but we gave them too much space and weren't compact enough," Klopp told BBC Sport. "We still had the bigger chances in the first half.
"I think the first goal is offside. Three players are offside - two for sure. They watched it and didn't think it was offside. We have to take it. This is good preparation for Saturday but we have to defend better."
Both teams made eight changes from their last Premier League matches, with Klopp handing Fabinho a first Liverpool start. Simon Mignolet, Alberto Moreno, Dejan Lovren and Nathaniel Clyne were also making their first appearances of the season.
After a sluggish first half, Liverpool had taken the lead through Daniel Sturridge's nicely improvised strike and looked on course to maintain their perfect start to the season until the late drama.
Hazard's stunning winner made it a disappointing night for Klopp's team, but it will all be forgotten if they can win the Premier League rematch at Stamford Bridge on Saturday.