There is no video assistant referee in the Women's Champions League group stage, unlike the men's competition.

"I can't remember the last time we were in a game like that when two humongous decisions like that have gone against us," said Hayes. "That is a lot tonight."

In the 77th minute, shortly after Sam Kerr had given Chelsea a 2-1 lead, Real Madrid forward Athenea del Castillo was caught by Jessie Fleming and went down in the penalty area.

A spot-kick was awarded by Danish referee Frida Klarlund but replays showed the foul had actually occurred outside the box, with Del Castillo's momentum and a slick surface meaning the World Cup winner skidded into the area.

Olga Carmona buried the penalty with her second goal of the game to salvage a late point for Real Madrid.

"I could see from the bench that the tackle was outside the box," said departing Chelsea boss Hayes.

"I'm absolutely shocked that those managing the game couldn't see that.

"Of course maybe Jessie shouldn't lunge in that area, but it happens clearly outside the box.

"At this level, when you are in control of a game and important decisions like that go against you, it makes it difficult."

'A terrible decision'

After conceding the late leveller Chelsea pushed for an injury-time winner and thought they had taken all three points when defender Millie Bright curled in a brilliant cross for Niamh Charles, who volleyed home from close range.

But seconds after the ball hit the back of the net the assistant referee's flag was raised and the goal was ruled out for offside.

Frustratingly again for the visitors, replays showed the call was wrong - Charles had timed her run perfectly and was comfortably onside.

"That is a terrible decision," former England defender Gilly Flaherty said on BBC Radio 5 Live immediately after the goal was chalked off.

"Charles is so far onside it is ridiculous. If I'm Emma Hayes looking back at that call, I am fuming. Chelsea should be walking away with three points. From the angle that we have seen it isn't even close [to being offside]."

Hayes, who will leave Chelsea to take over as head coach of the US women's national team in the summer, added she "could not understand the decision whatsoever".

"We score a really legitimate goal," she said.

"It is embarrassing. I had to check why it was disallowed. Was it Niamh [Charles]? No. Was it Sam [Kerr] interfering with the goalkeeper? She was about seven yards away, nowhere near the keeper. I think we've been robbed of what was a 3-1 game."

In October, Hayes said the Women's Super League "needs to have VAR in all games" after Chelsea's Guro Reiten was denied a goal despite the ball crossing the line in a narrow 2-1 win over Tottenham.

VAR was used in this summer's Women's World Cup and Uefa regulations