Australia’s John Millman has beaten German Jan-Lennard Struff in straight sets at the German Open to set up a tricky second round clash with world No.8 Dominic Thiem.

The world No.52 saved three break points to overcome Struff 7-5 6-3 in one hour and 31 minutes on clay at Hamburg’s Am Rothenbaum on Tuesday.

Meanwhile, Thiem marked his return from an injury layoff with a 6-4 6-2 first round victory over French qualifier Corentin Moutet.

French open runner-up’s Wimbledon adventure was cut short earlier this month after he was forced to retire with a back injury in his opening round match against Marcos Baghdatis.

Chasing his third hard court title of the season, the Austrian looked in fine form in Hamburg as he claimed a decisive break in the seventh game against Moutet to win the opening set.

Moutet, ranked 119th in the world, threatened a comeback when he secured an early break in the second set, but Thiem reeled off six consecutive games to seal victory.

Earlier in the day, Frenchman Gael Monfils moved into the second round with hard-earned 6-4 3-6 6-4 win over Italian Marco Cecchinato.

Monfils will next meet defending champion Leonardo Mayer, who recorded a 6-3 6-2 victory over Spain’s Albert Ramos-Vinolas.