Coco Gauff battles imposter syndrome on way into Miami Open semi-final

American No 4 seed beats Belinda Bencic 6-3, 1-6, 6-3 in quarter-finalGauff next faces 13th seed Karolína Muchová for a place in finalCoco Gauff may be struggling with an unfamiliar arm injury, indifferent form and the pressure of attempting to transform her serve with the entire tennis world watching, but the one quality that will never evade her is her fighting spirit.Under far from ideal circumstances, Gauffs mental toughness continues to guide her through the Miami Open draw and to her bes...