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Sinner, who is looking to win a record fifth consecutive Masters 1000 title, came from a set down on his way to a 6-7 (6-8) 6-1 6-4 victory in two hours and 20 minutes.

An hour-long opening set saw Sinner squander multiple break opportunities to pull clear of his opponent, and Bonzi made sure he made the most of that reprieve.

The Frenchman forced a tie-break against Sinner and was able to get the better of him, though the No.1 seed quickly found his groove and began to show his quality.

Sinner was able to reel off five straight games in the second set to ensure the match would go the distance, though more missed break points came in the first game of the third.

However, a timely break in the fifth game of the decider proved to be enough, with Sinner converting his first match point to tee up a clash with Danish qualifier Elmer Moller.

Elsewhere in the Spanish capital, there was no such trouble for Lorenzo Musetti, who emerged a 6-4 7-6 (7-4) victor over Hubert Hurkacz on Court Arantxa Sanchez Vicario.

But a top 10 seed did fall at the first hurdle, as recently crowned Munich Open champion Ben Shelton was beaten by Dino Prizmic, who won 6-4 6-7 (4-7) 7-6 (7-5).