Before mid-August, Grigor Dimitrov had lost all five of his FedEx ATP Head2Head match-ups with Juan Martin del Potro. The Bulgarian had never been able to solve the game of the big-hitting Argentine.

How things have changed. Dimitrov won his second consecutive match against del Potro on Wednesday at the China Open, coming through in a tight second-round affair 7-6(6), 7-5 to move into the quarter-finals in Beijing and boost his chances of qualifying for the Nitto ATP Finals.

“Very pleased that I was able to finish in straight sets. DelPo is an absolutely unbelievable competitor… Every time we play it’s absolutely stunning. He’s a great guy. I love practising with him. I love competing against him,” Dimitrov said.

The third seed was down a break in the second set and served at 2-5 to stay in the set. But Dimitrov ran off five consecutive games, including two breaks, to improve to 2-5 against del Potro in their FedEx ATP Head2Head series. The win adds 45 more points to Dimitrov’s Emirates ATP Race To London tally, giving him 3,185 points, 530 behind fourth-placed Dominic Thiem, who lost in Tokyo on Tuesday.

“I really needed that match… I just had to find a way today. I fought really hard, lowered my expectations, stayed positive,” Dimitrov said. “He’s the kind of competitor who can beat anybody… There’s not going to be any freebies against him. So I had to work, work and only work today. That was it. I didn’t think I played my best tennis but it feels awesome to win on days like that.”

See Who’s Pushing Dimitrov In The Emirates ATP Race To London

Dimitrov is seeking to make his debut at the season-ending tournament, to be held 12-19 November at The O2 in London. The right-hander will next face Spaniard Roberto Bautista Agut, who was leading Aljaz Bedene 6-0, 4-0 when the Brit retired.

Nick Kyrgios is through to the quarter-finals of the China Open in Beijing after finishing strongly to defeat Mischa Zverev 3-6, 6-2, 6-2 on Wednesday.

“I knew it was going to be tough,” said Kyrgios, who struck 11 aces and converted all four of his break point opportunities in the 82-minute win. “He plays a very old-school type of tennis, likes to come forward a lot.

“I got broken early in the first. Then I kind of knew I had to loosen up and find my rhythm a little bit. I started serving much better, started just relaxing. I knew I was going to feel pretty comfortable at some stage out there. Obviously just really happy to get through.”

Kyrgios goes on to face either Steve Darcis or Dusan Lajovic as he bids to advance to his fifth ATP World Tour semi-final of the season. The 22-year-old Australian reached his first ATP World Tour Masters 1000 final in August at the Western & Southern Open in Cincinnati (l. to Dimitrov) and has a 29-14 match record on the season. 

 Watch Live On TennisTV

 Watch Full Match Replays

As a returner, everything is stacked against you.

Firstly, you are facing the hardest shot hit on a tennis court, sometimes upwards of 140 mph. Blink, and it’s gone. Secondly, you begin in a statistical black hole, not even forecast to win three out of every 10 points you play.

Returning first serves is one of the toughest elements of our sport, with only a handful of players able to nudge their win rate higher than 30 per cent in this key strategic area. Depending on court surface and speed, average first-serve return win percentages for the Top 100 are typically between 26-30 per cent, with the average right at 28 per cent.

An Infosys ATP Beyond The Numbers analysis of Rafael Nadal’s resurgence to No. 1 in the Emirates ATP Rankings this season shows that the Spaniard’s performance in this key battleground has certainly aided his comeback.

Nadal is also No. 1 on tour in 2017 winning return points against first serves, at 35.2 per cent (971/2761). That metric bumps up to an astounding 43.4 per cent (454/1045) when you focus on just his clay-court matches.

2017 Season: Top 10 Points Won Returning First Serves

Andy Murray, who started 2017 as the No. 1 player in the Emirates ATP Rankings, is second best this season winning return points against first serves, at 34.7 per cent (640/1847).

Diego Schwartzman is the best returner on tour so far in 2017, winning an impressive 36 per cent (195/544) of his return games. He comes in third best winning return points against first serves, at 34.5 per cent (724/2099).

Other players in the Top 10 in first-serve return points won this season include Novak Djokovic (33.5 per cent), Roberto Bautista Agut (32.8 per cent), Roger Federer (32.5 per cent), Fabio Fognini (31.9 per cent), Dominic Thiem (31.8 per cent) and Marin Cilic (31.6 per cent).

Nadal, Djokovic and Murray have been No. 1 in this statistic for the past six seasons, dating back to 2011.

The technique used to succeed in this area is built around rebounding the power coming at you rather than trying to generate it all yourself. Blocking first serves with a short backswing and a defencive mindset lets these players neutralise the power of the first serve as quickly as possible in the rally.

The halo effect of the serve typically lasts for two more shots in a rally, where the server can lean on their groundstrokes and play aggressively because of the offence created behind their first serve. But these peak returners typically take that two-shot advantage away, often times pushing the server immediately onto their back foot for their Serve +1 groundstroke.

The primary target is straight back at the server, not changing direction at all, and trying to get the return as deep as possible to make the server have to move away from the shot instead of towards it.

There is no other strategy in our sport that makes you feel good winning only three out of ten times. It’s all about defence first, and looking to get back to neutral as quickly as possible through depth and direction right back at the server.