Stefanos Tsitsipas' second-round match against Jerome Kym was halted in Gstaad on Wednesday night due to the tournament's strict rule against playing without natural light.
The pair was tied at 6-4, 6-7(2), 5-5 when play stopped at Roy Emerson Arena. Tsitsipas had not faced a break point throughout the contest.
The clay-court event lacks floodlights, forcing the suspension until daylight returns. Play was scheduled to resume Thursday after 2 PM local time.
Tsitsipas, now ranked 88th, seeks his first back-to-back wins since April. The 27-year-old recently changed coaches, bringing in Thomas Perrin under Patrick Mouratoglou's supervision.