Yang Yong, the China Open's chief umpire of the silver group, shares his experiences with media during a press conference organized by sponsor Kappa. [Provided to China Daily]

BEIJING - The ugly scene that saw Serena Williams blow up at a lineswoman in the semifinals of last year's US Open remains vivid in many tennis fans' minds.

Similar rows have followed at the China Open's courts but, to the Chinese umpires, mistakes are part of the process of developing into the world's best.

"Everyone will make mistakes. The judges can get distracted by the players' complaints. The most important thing is you should focus on your next call," said Yang Yong, the China Open's chief umpire of the silver group this year.

They are four classifications for umpires in tennis (from low to high grade): white group, bronze group, silver group and gold group.

"Players who already have become testy during a close match are easily upset by false calls. It's understandable for them to do that, so a professional umpire shouldn't take it personally," said the 37-year-old during a conference jointly staged by the China Open organizing committee and its top sponsor, Kappa.

"There is a slogan among us that 'the most precise call will always be your next'. You just have to calm down as soon as possible and get on with your job on the court," said Yang.

Having been a linesman at all four Grand Slams since 2004 and being appointed the International Tennis Federation's chief umpire of the junior group, Yang has built a strong reputation abroad and won praise from the event's governing body.

"We knew little about the Chinese umpires before, but Yang's team's performance has made us confident about bringing more event to China in the future," said Tom Barnes, event supervisor of the Association of Tennis Professionals, after last year's Shanghai Masters.

However, Yang admits mistakes will always be made and the much-debated Eagle Eye system is emerging as a strong reinforcement for officials.

"While some people say Eagle Eye acts as a rival to the umpires, I would say that it more often provides support," Yang said."It guarantees the matches' fairness and players' benefits. And for me, I wouldn't feel any embarrassment if it corrected my calls."

Tennis in China has boomed with a series of top performances by women's players on the international stage.

Following in their footsteps, the Chinese umpires have also emerged. More than 50 umpires officiate at the four Grand Slam tournaments, including Zhang Juan, China's only professional umpire on the WTA Tour, who is the highest-rated umpire in China with a silver certification.