Thomas Tuchel hailed “key player” Mason Mount for taking his career to the next level with his stunning strike in Chelsea’s 2-0 Champions League quarter-final first-leg win over Porto. England internationals Mount and Ben Chilwell handed the Blues control of their last-eight battle as they scored two away goals during a fine performance in Seville. Blues manager Tuchel refused to accept his side have one foot in the semi-finals ahead of Tuesday’s second leg, which also takes place in Seville and will see Chelsea as the home side.