Bayern Munich players, coaching staff and fans at the Allianz Arena were in disbelief after they were denied a penalty for a handball by Joao Neves in their Champions League semi-final second leg against Paris St-Germain. Trailing the holders 1-0 on the night and 6-4 on aggregate, the German side's players surrounded referee Joao Pedro Silva Pinheiro at the half-hour mark when Vitinha rifled a clearance against his own team-mate Neves' arm inside the box.

But Pinheiro waved away the Bayern protests with the video assistant referee (VAR) also not intervening, leaving social media wondering why a spot-kick was not given. According to BBC Sport's football issues correspondent Dale Johnson, it was because of a little-known exemption within the handball law. According to the laws of the game, it is not a handball if "hit on the hand/arm by the ball which has been played by a team-mate (unless the ball goes directly into the opponents' goal or the player scores immediately afterwards, in which case a direct free-kick is awarded to the other team)."

"It covers when the ball is unexpectedly hit at you by a team-mate, even if your arm is away from your body - the law says you should not give away a penalty," said Johnson. "When Vitinha blasts the ball clear, could Joao Neves think the ball would be hit straight at him? Of course, this could be overridden by deliberate handball, but in the context of this situation, a penalty would not be expected to be awarded."

Reacting to the incident, former Liverpool defender Stephen Warnock told BBC Radio 5 Live: "It's a bit of an odd one. It's caught a few people out, the ruling of it, I didn't know about it. I think a lot of people are lost with the handball rule in the Champions League this season. We're almost wondering, is it going to be given, is it not going to be given? We don't know where we're at this season."

Former Blackburn Rovers and Chelsea striker Chris Sutton added: "The handball, I don't want to be critical of handball rules, but that's a really stupid one. So you can kick a ball and if the ball is in the air you can fist the ball and you're not going to get penalised for it."

Earlier in the game, Bayern manager Vincent Kompany and his players were also left incensed when PSG left-back Nuno Mendes escaped a second yellow card for a handball. Already booked for a foul on Michael Olise inside the opening eight minutes, Mendes handled a pass from Konrad Laimer, but the referee opted against cautioning him again, ruling the ball had struck the Bayern player's arm beforehand.

This article is the latest from BBC Sport's Ask Me Anything team.

Who has qualified for next season's Champions League?

Why did Bayern Munich players wear cockatoo T-shirts?

What is an Achilles injury?

Why the away goals rule no longer counts in Europe?

Who are the record Champions League goalscorers?