For all his undeniable luminosity, Novak Djokovic's occasional temper tantrums have often cast a shadow over his phenomenal success. 

Unlike the composed and poised demeanor exemplified by Roger Federer and Rafael Nadal, the Serb's fiery temperament tends to surface more frequently, resulting in regrettable incidents that attract attention and detract from his on-court brilliance.

The latest instance of Djokovic's frustrations reaching boiling point unfolded on Sunday night during his opening match against Holger Rune at the ATP Finals in Turin, Italy. 

Rune has long proven to be a formidable opponent for Djokovic, having achieved better results against him than many of his competitors in recent years. Rune secured victories over Djokovic in Rome, and came close to triumphing over him in the Paris Masters earlier this month.

It comes as no surprise that Rune, with his exceptional resilience, pushed the 24-time Grand Slam champion to his limits and repeatedly managed to recover from deficits. This relentless performance from Rune seemed to have taken its toll on Djokovic, who, in a moment of exasperation, resorted to stomping on two rackets, causing them to snap and break. 

Djokovic's sudden outbursts were far from commendable behavior on the court. However, it is worth noting that after venting his anger, he swiftly regained his composure. In an impressive display of mental fortitude, Djokovic proceeded to win the following three games consecutively, leaving Rune with no opportunity to mount a comeback. 

The result means Djokovic will end the year as world No.1 for an unprecedented eighth time. The victory also extends his stunning winning streak to 19 consecutive matches. 

Djokovic's year has been nothing short of extraordinary, defying his age to claim three Grand Slam titles and secure the all-time record for major titles. His recent triumph in Paris marked his seventh win there, and he also notched his 40th victory at a Masters 100 event, adding two more records to his ever-growing list of achievements. 

"It means a lot, obviously. You could see there was a lot of emotions on the court," Djokovic said of his incredible feat. "I could feel it. I was very eager to win tonight's match and get that monkey off my back. 

"I won Paris, which put me in a much better position rankings-wise, and I knew coming into Torino that all I have to do is win one match, so obviously a big objective, big goal is achieved. Everything else now is a bonus."

As Djokovic takes on the Finals in Turin, he sets his sights on a seventh title in the tournament, which would place him one step ahead of Federer.