When Cristiano Ronaldo scores a free-kick, you know about it.

Ever since his early days at Manchester United, the Portuguese has been mastering his trademark 'knuckleball' and it can produce some pretty spectacular results.

Memories of that remarkable strike against Portsmouth remain clear in the memories of football fans and he quickly transferred his free-kick prowess over to Real Madrid.

In fact, his first two seasons in Spain saw games with Zurich and Villarreal where he completed the rare achievement of scoring two free-kicks in a single match.

Nevertheless, when you fast forward to 2018, questions have started to be raised about Ronaldo and his consistency from set pieces.

Ronaldo's free-kick record

Although Ronaldo remains one of the finest takers in the world, damning comparisons have been drawn with Lionel Messi who has already scored 10 this year.

Meanwhile, Ronaldo only has one. Although, admittedly, it was his spectacular strike in the 3-3 draw with Spain at this summer's World Cup.

But it still raises some serious questions about the 33-year-old, especially when he's competing for responsibility with Paulo Dybala and Miralem Pjanic.

Ronaldo's free-kick attempts in 2017

Not only that but Ronaldo should be held to the standards he set himself and the numbers just don't compare to those early years.

It all makes a YouTube video on Ronaldo's free-kicks from 2017 look rather interesting, as it claims to show every attempt by him in that calendar year.

Although the video begins by showing his free-kick goal against Hungary, it then begins to rattle through the wayward attempts at Real and it just seems so out of character.

In fact, it highlights that Ronaldo only found the net three times from free-kicks that year - check out the clip down below:

For all the improvements Ronaldo has made as he gets older, it's bizarre that his free-kick taking has gone backwards.

And the video certainly foreshadows his even more frustrating record in 2018, which has led to so many comments regarding Messi.

The Barcelona superstar - who never used to compete with Ronaldo in this department - scored two in the win over Espanyol to continue his remarkable record.

At the end of the day, though, it remains a small part of the game and despite Ronaldo's free-kick record, he's continuing to produce goals from elsewhere.

Since moving to Juventus, he has proven himself in a third European league and has already broken a series of long-standing records.

But with suggestions Juventus will be his final club before retirement, fans would just love to see a few more knuckleball strikes before he bows out.

Who do you think is the better free-kick taker - Ronaldo or Messi? Have your say in the comments section below.