The partnership between Ms. Killman and Ms. Koroleva is relatively new. They've been a synchronized swimming duet for less than a year.
"For a synchronized swimming duet, being together for a year is a very, very short amount of time," Koroleva told reporters at the London Games. "I think we've definitely accomplished a lot in that year. Even though we're a new duet, we're at that level where we can be competitive with other duets who have been together for years."
On Sunday and Monday there will be 24 duet teams swimming in preliminary competition. The top 12 duets will advance to the final round on Tuesday.
Though Killman and Koroleva may not have had as much time together in the pool as the other teams, the pair was able to capture the silver medal in duets at the 2011 Pan Am Games, and they are both experienced synchronized swimmers in their own right.
Killman, from Ada, Okla., is a member of the US synchronized swimming team that won the bronze medal at the 2012 Spanish Winter Open. She was also named USA Synchro Athlete of the Year in both 2010 and 2011.
The duo will face stiff competition in London. They're up against the Japanese, who have won more synchronized swimming duet medals than any other country, as well as Russia and Spain who took the gold and silver medals respectively in 2008 at the Beijing Games.
The preliminary duet competition will continue Monday at 10 a.m. EST. It will be rebroadcast on NBC at 12:45 p.m. The finals will be on Tuesday at 10 a.m., and rebroadcast at 4 p.m.