The 13-year-old standing at the edge of a court in Reggio Calabria in 2009, handing balls to the Italian stars at a Fed Cup final, would never have guessed what came next. Jasmine Paolini was a ball kid that weekend, watching Italy beat the United States, and 17 years later she fired a serve into the back of the woman she once admired from the sidelines. That woman is Sara Errani, now her doubles partner and coach.

The misfire came in the round of 16 at the China Open, just 15 minutes into the match, with Paolini serving at 3-1, aiming at a three-peat in Beijing. The serve was struck at 152 km/h, and it hit Errani in the back. Errani walked to her chair holding her back with her left hand in obvious pain while Paolini, caught in a moment of horror, followed her over. The pain was felt in the Chinese commentator’s reaction as well, as he grunted in pain for a good six seconds on the air. 

Play resumed after a momentary break, and the eighth seeds carried on with their title defense, beating Katie Boulter and Yulia Starodubtseva 7-5, 6-1 to reach the quarterfinals.

The footage suggests she was standing upright at the net rather than crouching, though even a crouch would have offered little protection. A serve that is a little off target in doubles can find a partner, and the ball had nowhere else to go. These accidents are common in the format, and they almost never cause lasting tension between teammates. The only real damage is the sting.

Errani, being a 10-time Grand Slam champion in doubles and mixed doubles, has long learned to expect the occasional blow from a partner. A few months ago, she was on the other end at the Miami Open. In the opening-round match against Shuko Ayoma and Ulrikke Eikeri, at match point, Ulrikke hit a ball that landed outside, but Errani reached for it and hit Paolini’s head. The former world No. 4 immediately sat on the court, holding her head with both hands, but after a few seconds they broke into smiles and headed to the net for the handshake.

However, these incidents can take a dark turn. In 2014, during a World Tennis Team league match, Taylor Townsend hit a powerful forehand from the baseline that hit her partner, Liezel Huber, directly in the head, causing a concussion. Huber had to leave the court and was taken to a hospital while Townsend completed the match 1 vs 2 according to the tournament rules. Their opponents, Martina Hingis and Anastasia Rodionova, eventually won the match 5-1.

The relationship between Errani and Paolini now stretches beyond doubles. Errani is in the coaching team of the fellow Italian for 2026, taking charge of tactics alongside Danilo Pizzorno in big events, and the arrangement has been visible in the stands. At Wimbledon this year, the pair were entered in the doubles draw, but Paolini withdrew as her body struggled and she advanced deep into the singles draw. Instead of being upset, Errani was seen in her box throughout, cheering and guiding her.

Beijing has not treated Paolini well on the singles front. In four career appearances, she has managed to gather only four wins, and this time she fell to Daria Snigur in the first round after winning the opening set, a result that will drop her outside the top 30. That leaves doubles as her whole focus, and she and Errani have a clear target in front of them.

The Italians now face second seeds Luisa Stefani and Gabriela Dabrowski in the quarterfinals, a team that reached the US Open semifinals this year. Paolini and Errani are two-time defending champions in Beijing and the first pair to defend this title, so another win would take them a step closer to a historic three-peat, and back soreness will not be the reason to stop them from achieving it.