Rebecca Adlington is anticipating a fierce contest in the women's 800m freestyle final this evening.
The home favourite is defending her crown in the event, and faces stiff opposition from Denmark's Lotte Friis.
"Lotte and me are friends. We've been racing each other since the European juniors in 2004 and it's always been us two," The Telegraph quotes Adlington as saying.
"It's been one of us one year and then the other the next year – hopefully that doesn't mean it's her turn this time after I won the world's in 2011. Obviously it's going to be a battle tomorrow."
The 16-lenght event is expected to be a two-horse race between Adlington and Friis, with the Briton making it through the heats in 8:21.78 and her Danish rival clocking up the second-fastest time of 8:21.89.
The women's 800m relay is scheduled to begin at 7.45pm this evening.