Nacho scored one of the most bizarre free-kicks of the season during Real Madrid’s 4-1 victory over Sevilla at the Bernabeu on Sunday night.

When Marco Asensio was fouled on the edge of the box, it appeared to be the perfect opportunity for Cristiano Ronaldo to score his 400th - or 401st if you’re connected to Real Madrid - career goal for Los Blancos.

But while the Sevilla players were still helping Asensio to his feet, Nacho had curled the ball into the bottom corner of the net past Sergio Rico.

Madrid’s stars, Asensio included, ran off celebrating as the Sevilla players surrounded referee Alberto Undiano demanding answers.

Undiano hadn’t blown his whistle - so surely the Nacho’s free-kick should have been disallowed?

Video: Nacho's controversial free-kick v Sevilla

Watch the incident here…

At no point does Undiano blow his whistle. He turns around just as Nacho hits the shot and then signals to allow the goal.

Why Nacho's free-kick was allowed to stand

Many people were subsequently confused as to why the goal wasn’t ruled out, but referee Iturralde González has explained to Spanish newspaper AS why Undiano made the correct decision on this occasion.

According to González, the request for the distance to be measured to the wall (10 yards) has to come from the attacking side - so in this case, Real Madrid - and not the defending team.

If no request is made, the attacking team are free to take the free-kick as quickly as they want, provided it’s taken from the correct position and the ball isn’t moving when struck.

The ball was stationary when Nacho hit the free-kick, so the goal was perfectly legal.

Madrid take another step towards the title

Madrid went on to double their lead 13 minutes later through Ronaldo before Stevan Jovetic pulled a goal back for the visitors just after half-time.

Ronaldo then scored his second of the night in the 78th minute before Toni Kroos’s strike shortly afterwards added gloss to the scoreline.

The result means Real Madrid remain level on points with league-leaders Barcelona, who beat Las Palmas 4-1 at the same time.

However, Zinedine Zidane’s men will be crowned champions if they secure four points from their final two matches against Celta Vigo (Wednesday) and Malaga (Sunday).