Su managed to enter the final after a dramatic semifinal where three athletes all clocked 9.99 and all of them qualified to make it a rare nine-man final. It is also the first time in world championships history that a sub-10 second time has been required to reach the final.
"I was restless after the semifinal and I thought it was a long shot to enter the final. When the organizers announced my qualification, I was extremely happy," said Su, whose 9.99 equaled his own national record and made him the first Chinese to run under 10.
Su finished ninth in 10.06 in the final.
"After the heat and the semifinal, I felt I ran out of energy so 10.06 was good enough for me," Su said.
Su believed running along with top athletes like Bolt and Gatlin was both a honor and valuable experience.
"I felt honored as a Chinese to run in the 100m final. I think this experience will be very helpful for me as I know what it is like to compete with the world's very best," Su said.
Sunday saw four other gold medals find their owners.
In men's hammer throw, Poland's Pawel Fajdek won with a throw of 80.88 meters.
Dilshod Nazarov from Tajikistan took silver and Poland's Wojciech Nowicki had bronze, both posting 78.55 meters.
Joe Kovacs of the United States won the men's shot put in 21.93 meters and Germany David Storl took silver in 21.74. Jamaican O'Dayne Richards created a 21.69 national record to bag a bronze.
Olympic champion Jessica Ennis-Hill came back after the birth of son Reggie last summer to win her second world heptathlon title after fellow Briton Katarina Johnson-Thompson failed to score in the long jump.
Ennis-Hill garnered 6,669 points, beating into second place Canada's Brianne Theisen Eaton, who had 6,554. Latvia's Laura Ikauniece-Admidina took bronze with 6,516.
In the morning session, Moscow world championships bronze medalist Miguel Angel Lopez of Spain dashed China's hope to win their first men's 20km race walking title when he seized the victory in one hour 19 minutes and 14 seconds.
"The bronze medal in Moscow was important. I have been working very hard. I had strong rivals from China and Japan," said the 27-year-old.
China pinned high hopes on this event where 2012 London Olympic winner Chen Ding, London bronze medalist Wang Zhen and fourth-place finisher Cai Zelin joined force.
Wang, receiving two warnings, crossed the finish line 15 seconds behind Lopez. Chen had a disappointing ninth finish in 1:21:39 while Cai was fifth in 1:20:42. Canadian Benjamin Thorne came third in 1:19:57 to set a national record.
Title favorite Yusuke Suzuki of Japan, who smashed the world record at the Asian Championships in March in 1:16:36, withdrew mid-way.
