The 23-year-old was described by Mourinho as a "cold-blooded finisher" after he netted a hat-trick for Chelsea in Saturday's 3-1 Premier League win over Fulham. And Schurrle, who is set to make his 31st appearance for Germany against Chile in Stuttgart, puts his improved form and fitness down to his manager at Stamford Bridge.
"The move to Chelsea has made me better and stronger," Schurrle, who joined the Blues from Bayer Leverkusen last summer, told German daily Bild. "He illustrated that I needed to change, to be a little more robust in the Premier League. Even if I only got ten minutes, I wanted to show him that I have improved my aggressiveness and go harder into one-on-ones.
"Because I wasn't getting many games at the start of the year, I put in extra fitness work in the gym and pool, even on my days off. Mourinho is known for getting under players' skins, tickling and goading better performances out of them. The work is bearing fruit now."
Having made a rare start against Fulham, Schurrle is now eager to impress Germany coach Joachim Low in Wednesday's last friendly before the provisional World Cup squad is announced on 8 May.
Low has said "the clock is ticking" for fringe players, like Schurrle, to impress him and secure their Brazil berth. "The coach addressed the topic in a team meeting and stressed the need to make the next few months really count for anyone who wants to be at the World Cup," said Schurrle.
"It's good to build the pressure up on us three months before the World Cup. As players we know pressure is part and parcel of what we do."