Roger Federer, Rafael Nadal's Shot Variety Separates Them From Djokovic, Murray: Zverev

The Big Four of tennis have dominated the sport for over a decade. Pictured, (L-R) Andy Murray of Great Britain, Novak Djokovic of Siberia, Roger Federer of Switzerland and Rafael Nadal of Spain attend a ceremony for Carlos Moya's retirement during the Barclays ATP World Tour Finals at O2 Arena in London, Nov. 21, 2010. Clive Brunskill/Getty Images

Roger Federer and Rafael Nadal's shot variety is what separates the duo from Novak Djokovic and Andy Murray, according to Mischa Zverev.

Federer and Nadal dominated tennis for multiple years until the rise of Djokovic and later, Murray as the four players set themselves apart from the rest of the ATP Tour, forming the Big Four.

From 2015 to 2016 though, the sport started to get dominated mainly by Djokovic and Murray with the former winning five Grand Slams in that period while latter ended 2016 with a Wimbledon title and a year-end world No. 1 ranking.

However, the duo have since struggled with injuries while Federer and Nadal experienced career resurgences as they turned back to the clock to win a combined 17 titles and five Grand Slams since the start of 2017.

With both Federer and Nadal looking unstoppable despite seemingly being past their prime a few years earlier, Zverev believes the duo have something that Djokovic and Murray lack.

"They can do so much with the wrist," Zverev said, holding just one win in 11 combined meetings against the Big Four after defeating Andy Murray in last year's Australian Open. "[Andy] Murray and Djokovic's shots are more predictable."

"If the two [Nadal and Federer] play well, they cannot be defeated. When others play well, they can still be beaten. When the two play well, it's not so fun to face them."

Zverev also reflected on his five losses against Federer with his mother in attendance for one of the matches as she even started supporting the Swiss legend instead of him.

"Once my mother said that at least she had a good seat for the show," Zverev added. "She even clapped for Federer because she was so excited about him. She had forgotten that he was playing against me."

"I forgive her (laughs). And madness is when you look at videos of Roger and Rafa ten years ago: They play even better today! If I think of Roger's backhand of the last two years, that's incredible. He was already good."

Alexander Zverev and Mischa Zverev will take part in the Madrid Open. Pictured, Alexander (R) and Mischa Zverev of Germany participate in the Lotte New York Palace Invitational Badminton Tournament at the Lotte New York Palace in New York, Aug. 24, 2017. TIMOTHY A. CLARY/AFP/Getty Images

Zverev's younger brother, Alexander, is regarded as one of the top prospects of the next generation and is currently ranked No. 3 in the world. However, despite winning Masters titles, the 21-year-old is yet to really perform in a Grand Slam event as his brother advised him to lower his expectations.

"At the Grand Slams he still expects too much from himself," he explained. "But that's normal. If you win two Masters events, you want to play at least semi-final at the next Grand Slam. ... His qualities as a person: he is very ambitious, focused. He loves to play in the big stages and win. He is a winner. On the court, he forgets everything around him. It can be seen that he is an emotional person."

The next major event takes place in the Madrid Open from May 7-13 as Nadal will look to retain his crown and win his third title of the year.

Djokovic will take on Kei Nishikori in his opening match Monday while Alexander Zverev will first defend his Bavarian International title against fellow German Philipp Kohlschreiber in the final Sunday before featuring alongside his brother in Madrid.