How Mercedes can cause more headaches for Red Bull and McLaren

Mercedes had the winning momentum in Formula 1 prior to the summer break. Toto Wolff's team have won three out of the last four races after upgrades applied in Canada lifted them to the top. Mercedes are now a serious competitor for the likes of Red Bull and McLaren to contend with. There's more in the pipeline, according to the head of trackside engineering, Andrew Shovlin, who explains the key focus for the team.