Goal-hero Salomon Kalou insists Chelsea should have been awarded a first-half penalty when he was brought down just minutes before the interval.
Chelsea outplayed Inter Milan throughout but still lost the last-16 first-leg tie 2-1 in a pulsating match at the San Siro.
Inter had taken a third-minute lead through Diego Milito only for Kalou to level in the 51st minute.
But Esteban Cambiasso restored Inter's lead four minutes later to give Jose Mourinho's side a slight edge going into the return leg at Stamford Bridge on March 16.
But it could have been so different if Chelsea had been awarded a penalty minutes before the break.
Kalou appeared to be felled by Inter defender Walter Samuel but Spanish referee Manuel Gonzalez refused Chelsea's appeals for a spot-kick.
The official was surrounded by Chelsea players at the half-time whistle and Kalou was adamant it was a clear penalty.
"It was a penalty but the referee decided it wasn't so there is not a lot you can do about it," he said.
"I felt him touch my right leg but the referee told me that I did not have control of the ball any more when he touched me."
However, the English club were boosted after the game when it was discovered that goalkeeper Petr Cech, stretchered off with what looked like a knee injury in the second-half, had in fact damaged his calf.
But Kalou believes his away goal could prove vital in the return leg in west London.
"It is a good feeling to have the away goal," said Kalou. "Now we have to work on that and try to score at the Bridge and not concede."
Former Chelsea boss Mourinho believes his side will travel to his former stomping ground full of confidence but admits it will be an emotional return.
"We can go there with a legitimate ambition to go through," said Mourinho. "I don't expect anything other than people to be glad to have me back as we worked so well together.
"This time I will go back to a different dressing room, a different dugout but I know normally Mourinho is lucky at Stamford Bridge."
Chelsea coach Carlo Ancelotti saw enough from the match at the San Siro to be confident for the second leg.
"I think that what we saw tonight, we have the chance to turn it around," said the former coach of Inter's city rivals AC Milan.
"I think we played well. We leave without a positive result, but it's not an ugly one either."