Three-time Olympic champion Jeremy Wariner and 2005 world outdoor champion Bershawn Jackson each won 400-meter heats on Saturday at the US Indoor Track and Field Championships.
Wariner, competing in the meet for the first time, was the fastest qualifier for Sunday's final in 46.40 seconds while Jackson was fourth overall in 47.36, setting up a showdown between the rivals in one of the meet's feature races.
Wariner, a five-time world champion, took Olympic 400 gold in 2004 at Athens and was part of two US 4x400 gold medal Olympic relays.
Jackson, who last claimed a US indoor crown in 2010, took bronze in the 2008 Olympic 400 hurdles.
Olympic bronze medalist Janay Deloach Soukup won her third consecutive US Indoor long jump title with a leap of 6.80 meters. She will also compete in the 60m hurdles on Sunday.
London Olympic decathlon silver medalist Trey Hardee failed to finish in his 60m hurdles heptathlon heat Saturday morning, ending the 2009 and 2011 world champion's US title bid.
World junior champion Gunnar Nixon took the US crown with 6,232 points, winning the 60 hurdles in 7.93 seconds after taking the long jump (7.42m) and high jump (2.14m) on Friday to beat Curtis beach by 337 points.
Reigning Olympic champion Jenn Suhr was favored to claim her seventh US Indoor title in a later competition.
Matthew Centrowitz, a 2012 US Olympian who was third in the 1,500 at the 2011 worlds, was fourth-fastest among six qualifiers for the 800m finals in 1:47.94.
Amber Campbell's six-year reign as US indoor women's weight throw champion was ended by Gwendolyn Berry, who effort of 24.70m left Campbell second at 23.68.