Chelsea were far from their best in the first half against Ajax.
They endured the worst possible start to the game, with Tammy Abraham netting an own-goal after just two minutes.
Jorginho levelled the scores two minutes later from the penalty spot but that was as good as it got for the Blues.
The Dutch side would go into the break with a two-goal lead. Quincy Promes restored Ajax's lead before Kepa Arrizabalaga's unfortunate own-goal on the stroke of half-time.
Chelsea needed to come out of the blocks firing in the second half and they nearly found inspiration from an unlikely source.
Kurt Zouma picked up the ball up well inside his own half and decided he was going to go on a ridiculous run.
He raced past a number of players and threw in a couple of step-overs.
But, with only the 'keeper to beat, the Frenchman then skied his effort well over the bar.
All Frank Lampard could do was laugh after witnessing the extraordinary play from his centre-back.
Chelsea journalist Nizaar Kinsella gave him the very appropriate nickname: 'Cristiano Zoumaldo'.
Chelsea found themselves in an even bigger crisis shortly after when Donny van de Beek made it 4-1 to the away side.
But the Blues then produced a quite unbelievable comeback.
Cesar Azpilicueta pulled one back with 27 minutes remaining to give his side hope.
And then the turning point came five minutes later.
Chelsea were awarded a penalty when Joel Veltman handled in the box.
And shortly after Ajax were shown TWO red cards. Daley Blind received his marching orders for a foul in the build-up and then Veltman was sent off for dissent.
Jorginho scored the ensuing penalty and Reece James then levelled the scores with 15 minutes remaining.
Chelsea were unable to find a winner but they would have taken a draw when they were 4-1 down. What a game.