Sivkova won the 1997 Cadet World Championships at Tenerife. Her silver medal in the 1998 World Youth Games made her realise she could become a champion. She then took a silver medal at the 1999 Junior World Championships at Keszthely and the gold at the 2000 Junior European Championships in Antalya. She joined the senior national team in 2001. Her first competition with Russia was the European Championships in Coblenz, where they took the silver medal. They went on to win the gold medal in the World Championships in Nîmes. She climbed in 2003 her first podium in the Fencing World Cup with a gold medal in Prague and two bronzes in Tauberbischofsheim and Havana. She also reached the quarter-finals in the World Championships in Havana. These results pushed her to 6th place in world rankings.