The 30-year-old, nicknamed the 'Dragon', defeated Sweden's Mattias Falck 4-1 in the final.
The Qatar Table Tennis Association's success in hosting ITTF World Tour Platinum event lies in their competency backed by a team of hardworking professionals.
The former world No.1 had earlier won the 2013, 2016 and 2017 editions in the Qatari capital.
The “Chinese Dragon” overcame the blip in concentration after losing the opening game to beat compatriot Xu 14-12, 6-11, 11-8, 10-12, 7-11, 6-11.
The Olympic champion won 12-10, 11-7, 11-4 and 11-8 against fourth seed German Timo Boll. He will meet Japan’s Mizutani Jun in the last eight.
The Chinese needed six games to overcome Frenchman Tristan Flore 6-11, 11-5, 12-10, 9-11, 11-5, 11-7 as his handful of fans at the Ali bin Hamad Al Attiya Arena endured some anxious moments.
The familiar pair of Mohammed Abdulwahhab and Abdulrahman Al Najjar started off nicely against Ovidiu Ionescu and Alvaro Robles, but couldn’t maintain the momentum.
The Qatari capital last hosted the Team Worlds in 1994, but has been a venue of the ITTF World Tour Platinum Qatar Open since 1994.
Niggling left knee injury since last August saw the 30-year-old withdrew from the ITTF World Tour Opens in Czech Republic, Sweden, Austria and the 2018 World Cup.
Germany's Timo Boll will be making his 19th World Championships career appearance.
China top the men's, women's and team world rankings, while the country has won all 12 gold medals on offer across the last three Olympics.
The series, which will start in Shenzhen, China, on August 8, will also be held in Innsbruck (Austria) August 21-25, Townsville (Australia) 11-15 September, Fort Lauderdale (Florida) October 17-20 and Cardiff (Wales) December 13-16.
The duo of Abdulwahab and Al Najjar and Sultan Al Kuwari-Rowad Akaram finished second in the U21 and U15 finals respectively.
Qatar men's senior team suffered a shock 2-3 defeat against Bahrain while the women also lost 3-1 against Algeria.
On Sunday, he partnered Lim Jong-hoon to success in the men’s doubles. The No.6 seeds beat the top seeds Hong Kong's Ho Kwan Kit and Wong Chun Ting 11-8, 19-17, 9-11, 11-9.