Explained: Why Kai Havertz was allowed to retake crucial penalty for Chelsea against Borussia Dortmund in Champions League last 16

• Chilwell cross hits Marius Wolf's arm
• VAR says it's a penalty
• Havertz gets two chances to convert

WHAT HAPPENED? Borussia Dortmund players were deemed to have encroached in the box as Havertz ran up to take the first penalty, which he missed off the post, before clearing the rebound. The German converted his retake to give Chelsea a 2-1 aggregate lead.

The penalty call for handball was controversial itself, as VAR overturned the decision on the pitch and awarded the Blues a spot-kick. As a result, an in-form Dortmund side were furious at officials.

WHY WAS HAVERTZ ALLOWED A RETAKE? The key factor in the controversial decision was that a Dortmund player who prematurely entered the box cleared the ball after Havertz's miss. If there hadn't been a rebound, then there wouldn't have been a chance for Dortmund to kick the ball away to prompt a retake.

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THE REACTION:

The decisions that led to Chelsea going ahead on aggregate were highly controversial.

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And Blues players have been accused of entering the box first.

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But Kai Havertz won't care!

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THE BIGGER PICTURE: Remarkably, Havertz's goal marked the first time this calendar year that Chelsea have scored more than once in a match. It couldn't have come at a better time, with the Blues likely needing to win the Champions League to qualify for next year's edition given their position in the Premier League.

WHAT'S NEXT FOR CHELSEA? Graham Potter's men are next in action on Saturday against Leicester City.