Complex sentence: Hanna Kasyanova (née Melnychenko) of Ukraine entered the competition as defending champion, although the favourite for the competition is the silver medalist of 2013 World Championships Brianne Theisen-Eaton who is the world leader by a margin of more than 250 points.
Split into simpler sentences: Hanna Kasyanova (née Melnychenko) of Ukraine entered the competition as defending champion. Although the favourite for the competition is the silver medalist of 2013 World Championships Brianne Theisen-Eaton who is the world leader by a margin of more than 250 points.