It didn't take long for Cristiano Ronaldo to be beaten at his own game. 

The Juventus forward challenged his Instagram followers to a 'core crusher challenge' in Nike's Living Room Cup on Sunday. 

The name of the game: touch your toes as many times as possible while lying flat on your back. 

By the end of it, you might not have abs like Ronaldo, but the aim is to get as many people doing exercise at home during the coronavirus lockdown as possible. 

Athletics star Caster Semenya quickly beat the Portuguese's record. While he managed 142 reps in 45 seconds, the Olympic gold medallist easily surpassed him with 176.  

Footballers haven't found it so easy, however, and Manchester United's Bruno Fernandes probably regrets bringing his attempt to his compatriot's attention. 

The playmaker wrote after notching up 117 reps in the allotted 45-second time:

"#NikeLivingRoomCup - Week One. 117 Abs in 45 seconds. Not bad for a Sunday…"

It's an impressive attempt, but it clearly didn't win over Ronaldo, who replied on his own Instagram story: 

"Train your arms instead!"

Ouch. 

Of course, it's not the first time in recent months Fernandes' name has been mentioned in the same breath as his idol.

Having moved to Old Trafford from Sporting Lisbon to follow in the footsteps of the five-time Ballon d'Or winner, the 25-year-old has been a revelation. 

Before the season was interrupted, he had already chipped in with two goals and three assists in just five league games. 

If that's a sign of things to come, then the early comparisons with Ronaldo might be justified - even if he pales in comparison to the legend when it comes to his abs workouts.