Mardy Fish recently compared Roger Federer and Jannik Sinner's respective rivals, with the American former ATP star blatantly questioning the level of players that the reigning World No. 1 is currently having to deal with. Fish's comparison stemmed from a statistic about Sinner compiled from the results he enjoyed on hard courts during the 2024 tennis season.On Sunday, August 10, the official X (formerly Twitter) handle of TNT Sports shared the statistic of Sinner having won 94.8% of the matches he played on hard courts last year; the third best of all time on the surface. So far this year, the reigning Australian Open, Wimbledon and US Open champion has 38 wins and two losses spanning all surfaces after a victorious start to his Cincinnati Open campaign, with a win rate of 95%.Only the legendary, now-retired Roger Federer sits above the Italian in terms of most successful hardcourt seasons of all time, with the Swiss occupying both first and second spots. In 2006, the former No. 1 and 20-time Major champion won 59 of his 61 competitive outings on hard courts, which translates to a 96.72% of wins. The previous year, he'd lost only one of 51 matches on the surface; a win rate of 98.03%.Former No. 7 Mardy Fish, who in his playing days was widely regarded as a 'hardcourt specialist', played Federer on nine occasions, and the Swiss' American former rival dismissed Sinner's 2024 stat. Reacting to TNT Sports' post on X, Fish compared the level of players the Swiss had to compete against back in the day and the level of Sinner's rivals nowadays The 43-year-old wrote:"Now do who Roger had to deal with against who Sinner has to deal with… I’ll hang up and listen"Mardy Fish @MardyFishLINKNow do who Roger had to deal with against who Sinner has to deal with… I’ll hang up and listenFederer finished 2005 as the year-end No. 1. At the time, his top 10 rivals included Rafael Nadal, Andy Roddick, Lleyton Hewitt, Andre Agassi and Gaston Gaudio, who were all Major winners. In 2006, the Swiss once again finished as the top-ranked singles player on the ATP Tour, with with fellow Major titlists Nadal and Roddick remaining in the top 10.In 2024, Jannik Sinner ascended to No. 1 and finished the year there, with Grand Slam champions Alcaraz, Daniil Medvedev and Novak Djokovic also featuring in the top 10. However, Medvedev and Djokovic, despite their top 10 finishes last year, had underwhelming seasons for the most part. Right now, only Alcaraz and Djokovic are Major winners in the top 10 apart from the Italian.Jannik Sinner's most recent hardcourt loss came at China Open 2024Jannik Sinner (left) and Carlos Alcaraz (right) at the 2024 China Open (Source: Getty)In early October 2024, Jannik Sinner clashed against Carlos Alcaraz in the final of the China Open in Beijing. The Italian clinched the first set 7-6(6), but the Spaniard stormed back into the contest, taking it to a decisive third set by taking the second 6-4. The decisive third went to a tiebreak as well, but here, it was Alcaraz who emerged victorious 7-6(3) to win the ATP 500 event.Since his loss to the Spaniard in the Beijing final, Sinner has featured in four hardcourt tournaments and won three of them; the 2024 Shanghai Masters and ATP Finals, and this year's Australian Open, where he successfully defended his title.Jannik Sinner's fourth outing at a hardcourt event since his Beijing loss to Alcaraz is the ongoing Cincinnati Open. The Italian is the defending champion in Cincinnati, and got his title defense underway with a 6-1, 6-1, second-round demolition of Daniel Elahi Galan. The top seed is set to face No. 30 seed Gabriel Diallo next.