Matteo Berrettini made a winning return in his first match back since hand surgery after defeating Radu Albot at the Stuttgart Open.
The world number 10 was forced to sit out the ATP clay season after undergoing surgery following his withdrawal from Miami.
But the Italian was in fine form upon his return as he saw off Moldovan qualifier Albot with a battling 6-2 4-6 6-3 victory to get his grass-court season underway.
Following his last-four appearance at the Australian Open, Berrettini will be seeking another deep run at Wimbledon this year, after reaching his maiden grand slam final there last summer.
The former world number six will have to wait to discover his quarter-final opponent however, after rain forced a suspension in the match between Lorenzo Sonego and Jan-Lennard Struff.
Sonego took the opening set in a tie break, with the match to be finished on Thursday.
At the Rosmalen Grass Court Championships, Jenson Brooksby likewise saw his match against Hugo Gaston brought to a standstill by overhead conditions, with the American leading 4-2 in the first set.