TOKYO—Britain enjoyed a one-two success in the men’s 200m freestyle on Tuesday, while Russian swimmers ended U.S. dominance in the 100m backstroke, and Kaylee McKeown gave Australia’s women more Olympic gold to celebrate at the Tokyo pool. On the same day, Alaskan teenager Lydia Jacoby upstaged her 2016 Olympic champion teammate Lily King to win a surprise gold medal in the women’s 100m breaststroke. Tom Dean won gold and team mate Duncan Scott the silver in the 200 freestyle as the two British swimmers left their rivals in their wake, Brazil’s Fernando Scheffer taking the bronze. It was Britain’s second swimming gold following Adam Peaty’s victory in the 100m breaststroke on Monday and left Dean reflecting on the adversity he has faced on his journey to gold. “It’s amazing. It’s a dream come true having a gold around my neck … I contracted COVID twice in the last 12 months …