Injuries to Rene Adler and Robin Zentner thrust the 20-year-old goalkeeper into the first team in Mainz's crucial relegation six-pointer in Hamburg. He proved equal to the task, almost single-handedly salvaging a 0-0 draw by saving all six shots on his goal – including Filip Kostic's penalty. It was the first time since August 2015 that a goalkeeper kept out a spot-kick on his Bundesliga debut.
Watch: Florian Müller - March Rookie of the Month candidate
Mainz's current plight in the thick of a relegation battle does not seem to faze the custodian either. "I'm a laid-back kind of guy," he said after his heroics in Hamburg.
The German youth international, who joined Mainz from 1. FC Saarbrücken at the age of 15, subsequently kept his place in the side and took to the field against Schalke and in the Rhine-Main derby away to Eintracht Frankfurt.
"Florian's been exceptional," said Mainz head coach Sandro Schwarz of his young shot-stopper's first top-flight outings. "He's a hugely talented goalkeeper. We always knew he'd make it into the professional game."
Indeed, the 6'3" (192cm) 'keeper is held in such high regard that the club recently extended his contract until 2022.
Given his performances in his first three outings, it is easy to see why. Müller saved 71 per cent of all shots on his goal, a tally in line with the Bundesliga average – and not at all bad for a rookie. Furthermore, he has kept out 75 per cent of all the opposition's clear-cut chances.