Australian Alex de Minaur is out of the ATP Tour’s Rome Masters after defeat at the hands of German qualifier Dominik Koepfer.

Koepfer beat de Minaur, a US Open quarter-finalist last week in New York, 3-6 6-3 7-6 (8-6) on the red clay in the Italian capital.

Koepfer faces a second-round showdown with French fifth seed Gael Monfils.

Earlier on Tuesday, Australian John Millman moved into the round of 32 in Rome with a hard-fought 7-5 7-6 (7-2) win over Portuguese lucky loser Joao Sousa.

His reward was a match-up with eighth-seeded Argentine Diego Schwartzman.

Also on Tuesday, Russian ninth seed Andrey Rublev cruised through to the second round with a 6-4 6-4 win over Argentine qualifier Facundo Bagnis.

German Jan Lennard-Struff was defeated 6-1 7-6 (7-5) by Argentine qualifier Federico Coria, who will meet Italian fourth seed Matteo Berrettini in the next round.