(CNN) -- Norway's Alexander Dale Oen won gold in the 100m breaststroke in an emotional day of medal winning at the FINA World Championships in Shanghai.
The 26-year-old pointed to a Norwegian flag in reference to the shootings in his home country on Friday that claimed the lives of over 90 people.
"It's a very special medal after what happened in my country in the last days," he told FINA's official web site after his victory.
"Seeing the flag, hearing the national anthem, everything was coming back and even though it's been three days, it is still a shock."
Elsewhere, tears were shed when the Brazilian Cesar Cielo won the 50 meters butterfly, but not from all quarters.
Cielo had been banned for alleged doping offences earlier in the year but, after taking his case to the Court for Arbitration in Sport (CAS), the ruling was overturned four days before the race.
As Cielo wept during the medal ceremony, other swimmers made pointed gestures, unhappy at his appearance. It was reported that some members of the crowd jeered his victory too.
"This gold has definitely a different taste than the other ones. That was probably the hardest medal in my life; I knew I was going to race against the world's best, and to be able to compete after what I have been through this last month is really a blessing," Cielo told FINA's official web site.
"With what happened, it was a time to test how much I could take and if I would be able to stand up again, and I am really proud of myself for doing this. Medals are important but I cannot imagine my life without the environment of swimming."
The U.S. and China won their first gold medals when American swimmer Dana Vollmer triumphed in the 100m butterfly and 15-year-old Shiwen Ye secured the 200 meter individual medley for the hosts.