Even at 37 years old, Aritz Aduriz knows where the back of the net is.The forward has been plying his trade at Athletic Bilbao since 2012 and boasts an impressive record of 170 goals across 379 appearances.He is something of a cult hero in the Basque Country and despite age surely catching up on him soon, his brilliant ability in the air continues to make him a massive threat.When you have Aduriz playing up front, you stand a very good chance of finishing the season with a 20-goal striker and that can be simply invaluable in La Liga.The 2018-19 campaign has thus far represented 'normal service resumed' with Aduriz boasting five goals in 12 outings, most of which coming in the Copa del Rey.

Athletic Bilbao 1-1 Real Valladolid

However, he made an impact during the league clash with Real Valladolid this weekend in a game that will have Bilbao fans kicking themselves.

Oscar Plano scored a last minute equaliser for the visitors, condemning Les Leones to a spot in the relegation zone and with just two wins in 17 matches.

It also denied Aduriz the opportunity to become the hero on the night, with the veteran striker opening the scoring in remarkable fashion after 45 minutes.

Aduriz's nonchalant penalty

Bilbao won themselves a penalty and Aduriz has proven himself to be prolific from 12 yards, only missing nine spot kicks across over 40 attempts throughout his career.

However, he's never scored a penalty like he did against Valladolid, using a humiliating technique that has quickly gone viral across Twitter.

As if playing in a five-a-side tournament, Aduriz decided against a run-up entirely and simply slumped backwards before slotting the ball past Jordi Masip.

It really was quite something - check out the video down below:

Utter humiliation. 

It must have taken some serious nerve from the Bilbao striker to even try the technique in the first place and it could have easily backfired in front of thousands.

There have been a few examples of one-step penalties in the past - Jimmy Floyd Hasselbaink tried it on occasion - but we've never seen it executed with such nonchalance.

Not giving yourself a full run-up seriously limits what you can do and generating power becomes much harder, hence Aduriz's decision to place his finish.

Why the 37-year-old decided to try it in this particular game is beyond us, but the element of surprise is now gone and he'll surely revert to his former technique.

For the time being, though, football fans can enjoy a superb moment of audacity from a cult hero at Bilbao.

It also emerged in a month where Borussia Dortmund were up to some inventing of their, producing a genius free-kick against Werder Bremen. Check that out here.

What's the most audacious penalty you've ever seen? Have your say in the comments section below.