Who is Alexander 'Sascha' Zverev, and why is he being hailed as tennis's 'next big thing' ahead of US Open?

As Alexander Zverev shook his head after botching a volley when up match point against Rafael Nadal in Indian Wells last March, he looked as if he wanted to be anywhere but on a tennis court. 

Still only 18 at the time, Zverev went on to lose the match and afterwards looked close to tears as he lamented: "On match point I sucked, so that was it. I missed probably the easiest shot I had the whole match. That's what happened."

A year and a half on and Zverev has gone from lanky teenager to 20-year-old baseline behemoth with two Masters titles to his name and a career-high world ranking of No 6. He quickly recovered from the devastation of losing to Nadal and said phlegmatically this year that "every good tennis player has to have a short memory".

Tennis experts are wary of forecasting who the 'next big thing' might be - they have been scarred by too many false dawns over the last decade - but Zverev has something a little extra special, so much so that Nadal and Roger Federer are among those who have already tipped the youngster for greatness. 

Zverev's defeat of Federer in the Rogers Cup final earlier this month to win his second Masters title of the year suggested that he could be about to make a major breakthrough, and the bookies have installed him as the third favourite for the US Open, which begins on Monday, August 28.

Before the tournament starts, Telegraph Sport takes a look at what makes Zverev so exciting and why he could be the long-term successor to the reign of the 'Big Four'. 

Upbringing

Zverev, a German national, was born in Hamburg and raised by his mother Irina Zvereva and father Alexander Zverev Sr, both of whom are former Russian tennis players. 

Alexander Jr - or 'Sascha' as he is known - began playing tennis himself almost as soon as he could walk, and quickly followed in the footsteps of his older brother Mischa, who is nine years his senior and was already on the path towards joining the ATP Tour. 

The brothers were coached by mama and papa Zverev, and Irina told Telegraph Sport earlier this year that Sascha and Mischa had an insatiable appetite for playing tennis growing up. "Both kids sometimes used to say, ‘Last ball’, and I would have to play one hour more," she said. "With Sascha, especially, we know when we want something to stop, one of us must lose to him at something – tennis, cards, backgammon. There’s no other way. And then after he’s happy, we can go to dinner or go to sleep."

Zverev says of Irina and Alexander Sr: "My parents are very calm. They understand what I am doing, and they have both been playing pro tennis so they know how to behave."

Alexander Sr is still Zverev's coach now, and he is helped by former French Open winner and world No 1 Juan Carlos Ferrero. 

Mischa was talented and has enjoyed a successful career - he beat Andy Murray at the Australian Open in January and has been ranked as high as 25 in the world - but Sascha was clearly extraordinarily gifted. As Mischa entered junior tournaments, Sascha would watch from the sidelines and then knock up with players a decade older like Novak Djokovic and Gilles Simon without any hint of being overawed. 

It wasn't long before Sascha began to make a name for himself on the junior circuit, and as a precocious 15-year-old he won the prestigious Trofeo Bonfiglio in Milan four years ago. Previous winners of the event include Bjorn Borg, Ivan Lendl and Stefan Edberg, and the buzz of excitement around Zverev intensified, with the question becoming when not if he would become the world No 1. 

Breakthrough

Zverev became the No 1 ranked junior in October 2013, and he backed that up by winning the Australian Open junior title at the start of 2014. 

Following the victory in Melbourne he started playing on the main tour, and cracked the top 100 for the first time in June 2015 after winning the Heilbronn Challenger in his native Germany in May 2015. 

The agonising defeat to Nadal at Indian Wells then served notice of his rapid improvement, and it wasn't long before he won his first ATP title as he claimed the St. Petersburg Open last September. 

Zverev has continued to get better and better, winning five titles this year - including two Masters events in Rome, where he crushed Novak Djokovic in the final, and Montreal - on his way to breaking into the world's top 10. 

The 20 greatest tennis players of Open era

What makes him so good?

Imagine a 6ft 6in version of Novak Djokovic who can bang down aces with the seemingly effortless ease of a mid-1990s Pete Sampras. 

Pretty scary right?

Zverev of course is not yet at the level of either of those two legends of the sport, but when he's on song he's not far off. His movement and athleticism is Djokovic-esque and his backhand is reminiscent of the Serb's, but with extra pop. Zverev was ambidextrous growing up, which partly explains how he is able to get so much power with the double-hander. 

Zverev himself puts his excellent backhand down to the stellar guidance of his mum: "My father is my coach," he says. "But when I was younger my mother was guiding me more. I think I have pretty good technique, which my mum did at a young age, so credit to her for that. My backhand, in particular, is 100 per cent down to my mum."

When serving, Zverev has become increasingly adept at utilising his 6ft 6in frame to bang down aces and produce more variety with spins and kick to keep his opponents guessing. 

In the Rome final against Djokovic, Zverev demolished the best returner in the history of the game with the accuracy and power of his serving, and did not face a break point all match.

Even if his opponent is able to get the Zverev return back in play, the German is so adept at quickly getting on the front foot in the point with the power and depth of his forehand. He is also an exquisite shot maker, and as his brother Mischa says: "I think the last generation, especially Andy and Novak, was so professional. The focus was on perfection. I think Sascha and Dominic [Thiem], and this whole generation, are going to be a little more creative."

The only real weakness in Zverev's game is his volleying - as demonstrated against Nadal in Indian Wells - which is a source of amusement and frustration to his family given that older brother Mischa is one of the best volleyers in the game. 

Physical specimen

When Zverev was climbing up the junior ladder, he was very slender and lanky in build, but still able to generate phenomenal power. 

The worry for the Tour was that once he filled out, he was going to be a formidable physical specimen. The job of turning him from gangly teenager to full-formed tennis superman fell to fitness trainer Jez Green, who left Andy Murray's camp to join team Zverev in 2013. 

At a glance | Alexander Zverev

Zverev's transformation is not yet complete - his legs are still telescopically thin - but he is acquiring more muscle and becoming an even more imposing proposition. Green was a major factor in Murray's physical metamorphosis at a similar age, and is known as a hard task-master, something that Zverev is happy to embrace.

"For Sascha, it’s a very difficult day if Mr Jefferson [Green] say it’s time to rest," explains Zverev Sr. "He knows he cannot go to party, because you must go in bed, prepare for next day. But his party is go to trampoline sometimes, ski or water-ski."

Last year, Zverev ended his season early in order to have an extended and even more punishing training period. 

A note of caution

For all his brilliance in Masters events this year, Zverev's record at grand slam remains disappointing. He is yet to reach a major quarter-final and suffered a frustrating five-set defeat to Milos Raonic in the fourth round of this year's Wimbledon. A few weeks earlier, Zverev had exited the French Open at the first round stage after a limp performance against Fernando Verdasco that he described as "absolute s***".

Until he is able to prove himself over the best of five set matches, the onus will be on Green and the rest of the team to add the necessary durability to go alongside Zverev's explosiveness.

What's next?

The US Open would be the perfect time for Zverev to show that he is ready to take the next step up and make a breakthrough at grand slam level.

Were he to win the tournament then Zverev would go as high as No 4 in the world and all but book his place at the year-end ATP World Tour Finals in London. 

But even if he doesn't quite manage to claim the title at Flushing Meadows next month, the question remains when not if Zverev will start to dominate men's tennis.