(Reuters) - U.S. Open runner-up Alexander Zverev says it is “absurd” he remains behind Roger Federer under the ATP Tour’s revised rankings system during the COVID-19 pandemic, given that the Swiss was out injured for more than a year. The ATP, which runs the men’s tour, froze the rankings last year during the five-month shutdown of professional tournaments with countries imposing lockdown and sealing borders to check the spread of the novel coronavirus. When the tour restarted in August a revised system was put in place for calculating the rankings, which determine a players’ ability to enter events and receive seedings. “The ranking doesn’t really matter, especially with the system that we have now,” Zverev, who is ranked seventh, told reporters ahead of this week’s ATP 500 tournament in Acapulco, Mexico. “I should be top-four, top-five in the world right now in the normal ranking system. But the ranking system that we have now is a little bit absurd.” Federer, who only returned to the tour in Doha last week, has been a big beneficiary of the new system with the 20-times Grand Slam winner ranked sixth despite a lengthy break due to double knee surgeries last year. “I am the biggest fan of Roger Federer but he hasn’t played in a year and he is ahead of me in the rankings,” the 23-year-old Zverev said. “I played a Grand Slam final, a Masters 1000 final, won two tournaments. “Right now the ranking system is just so messed up that you don’t need to pay attention to it.” The rankings traditionally operate on a “Best 18” results basis over 52 weeks but the system was changed to cover a 22-month period from March 2019 through December 2020 to allow players flexibility to skip events amid the pandemic. The revised system for calculating rankings was this month extended through the week of Aug. 9 and the ATP anticipates that the traditional process with points dropping off on 52-week basis will restart after that.