Oddly the 21-year-old world number three is yet to progress past the last 16 of a grand slam but he now has three Masters 1000 titles to his name and against Thiem played with a swagger that suggests that his record in the majors will improve soon.
The second seed broke a nervy-looking Thiem in the opening game thanks to a double-fault and was never really challenged as he produced a clinical serving display in which he did not even offer up a break point.
Zverev, who did not face a break point all tournament, broke again right at the start of the second but squandered the chance of a double-break two games later as Thiem, conqueror of Rafael Nadal in the last eight, hung on.
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There was no chance of a let-up from Zverev though and he remained focussed throughout, winning on his first match point when his Austrian opponent returned long.
Zverev becomes only the fifth active player to win at least three Masters 1000 titles -- joining the 'big four' of Rafael Nadal, Roger Federer, Novak Djokovic and Andy Murray.
He will roll on to try to defend his Rome title next week having won nine matches in a row on clay, dropping only one set in the process during title runs in Munich and Madrid.
"Hopefully I can continue this kind of streak in Rome," Zverev told reporters.
"Winning two titles in two weeks is great. Winning a Masters, another Masters, is unbelievable. But before the French Open, there's still Rome where I'm the defending champion...
"Obviously I didn't get broken one time (in Madrid)," he added. "But I don't think I faced breakpoints in the whole tournament. For me, this is an amazing stat to know in the back of my mind."
(Reporting by Martyn Herman; Editing by Toby Davis)
