Russia's Roman Vlasov and German Frank Staebler won titles Monday in the opening session of the wrestling world championships in Las Vegas.
Staebler defeated Korea's Ryu Han-Soo at 66 kilograms (145 pounds), and Vlasov beat Denmark's Mark Madsen at 75 kilograms (165 pounds).
Top-ranked Armenian Artur Aleksanyan beat Iran's Ghasem Rezaei 3-0 in 98 kilograms (215 pounds) to win the world title.
American Andy Bisek won his bronze medal match after earning the U.S. a spot in the Rio Olympics with a top-six finish at 75 kg.
Staebler beat top-ranked Serbian Davor Stefanek before defeating Ryu 4-1.
Vlasov, who won worlds in 2011 and the London Olympics in 2012, beat a pair of world champions to reach the finals, where he decisively defeated Madsen 6-0.
The U.S. team, which typically struggles in the Greco-Roman discipline, got off to a torrid start. They won their first five matches, but only Bisek qualified for a medal match.
Bisek went 3-1 in the opening session, losing 9-0 to Madsen before beating Bulgaria's Yavor Yanakiev 1-0 for a spot in the third-place match. Bisek then beat Iran's Saied Mourad Abdvali 2-0 for his second world bronze in as many years.
Bryce Saddoris, who wasn't ranked in the top 20 at 66 kg, won his first two matches before Staebler beat him in the quarterfinals. Saddoris took a 4-0 lead in his repechage match, but he got hit in the head and eventually fell 5-4.
The worlds continue Tuesday with Greco-Roman titles - and spots in Rio - on the line at 59 kg (130 pounds), 71 kg (156 pounds), 80 kg (176 pounds) and 130 kg (286 pounds).