It was the key moment of a momentous game.
Thiago Silva rose highest from the corner and planted his header perfectly over the desperate stretch of Thibaut Courtois to give Paris Saint-Germain an away goals victory over Chelsea in the last-16 of the Champions League.
Yet video footage seems to suggest that John Terry blocked teammate Gary Cahill as the cross came in. PSG captain Silva manages to side-step the pair, gain leverage over Terry and place his header to perfection.
The incident is likely to infuriate manager Jose Mourinho, as normally the Premier League leaders are rock solid when it comes to defending set pieces. Yet on Wednesday night the French champions scored twice from corners, with poor marking to blame.
Cahill opened the scoring for Chelsea with nine minutes of normal time remaining. Ex-Blues defender David Luiz then rifled in a front-post header to take the game into extra-time.
Silva was penalised for handling in the area, with Eden Hazard expertly dispatching the spot-kick to give the Blues the lead once more.
Then came the defensive cock-up and Chelsea's Champions League's hopes evaporated.
It is the first time since 2009 that Mourinho has been eliminated from the competition at the round of 16 stage.
Premier League focus
The Blues now have only the league to focus on. They are five points clear of champions Manchester City with a game in hand. With the Capital One Cup already won, Mourinho believes that if they secure the Premier League title as well it will still have been a 'fantastic' season.
They face Southampton at home on Sunday, whilst City travel to Burnley on Saturday evening.