Defeats are always painful in sport and when it comes to tennis, they can be heart-breaking as the margin of error can sometimes be incredibly small. And Roger Federer has faced his fair share of heart-breaking losses.
Having been dominated by Rafael Nadal in the early part of his career, Federer found a way to defeat the Spaniard and claim his 18th Major at the 2017 Australian Open. The Swiss has lost just once to Nadal since then while registering four more wins; his most recent triumph came in the Wimbledon semifinal this year.
While Federer solved the Nadal problem, he has another, perhaps bigger issue now - Novak Djokovic. But the story of the Federer vs Djokovic rivalry is different from the Federer vs Nadal one, as the Swiss has come close to beating Djokovic on many occasions before eventually losing his way.
The head-to-head record between Federer and Djokovic currently stands at 22-26 in favor of the Serb, and the last time Federer won against Djokovic was in the round-robin stage of the World Tour Finals in 2015. Djokovic was quick at getting revenge though as he defeated Federer in the final 6-3, 6-4.
Since then, the two players have faced each other four times and Djokovic has defeated Federer in all of those matches. Except for the final in Cincinnati last year, Federer has managed to win a set every time, but failed to sustain the momentum.
At the Wimbledon this year Federer seemed to have finally turned the tide in his favor as he had two match points in the fifth set on his serve. But he failed to capitalize on either of them and ended up losing the match.
As positive as Federer appears while talking to the media, that defeat seemed to have crushed his spirit. The baggage from Wimbledon continued loomed large over the next few months, as Federer lost early at Cincinnati, New York and Shanghai.
But he seemed to have recovered a little at Basel, as he shook off the disappointment to produce some vintage tennis. Federer ended up winning a record 10th title at the Swiss Indoors, defeating Alex de Minaur in the final.
At the ATP Finals this year, Federer has been placed in the same group as Djokovic, along with Dominic Thiem and Matteo Berrettini. Both Thiem and Djokovic have defeated Federer this year, and that could have an impact on the Swiss' psyche.
Federer will have to play Djokovic once in the round-robin stage, and it will be interesting to see how he performs against the Serb. While youngsters like Thiem, Alexander Zverev and Andrey Rublev have found a way to defeat Federer this year, the pressure of playing against Djokovic at the season-ending championships is at a completely different level.
For Federer to have any chance of upsetting Djokovic, he'd have to wok on his break-point conversion rate. He has been struggling mightily to convert break points since the start of 2018; he currently stands in 90th place on the list of players with highest break-point conversion rates, with 41.20%.
Federer has been able to convert just 4837 out of the 11741 break points he has had in his career, whereas Nadal is in second place with a conversion rate of 44.96%. Djokovic also stands at the 7th position with 4021 out of 9059 break point opportunities converted.
With Nadal's form in question once again after his withdrawal from the semi-finals of the Paris Masters earlier last week, Federer would fancy his chances in London. But Djokovic continues to be a major obstacle, and it would take something special from Federer to improve his break-point conversion rate and overcome the Serb.
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Federer's fans would be hoping that he can bounce back and end the season on a good note, but the stats and his recent record against Djokovic suggest otherwise.