Tomas Berdych came from a set down to beat qualifier Matthias Bachinger in the first round of the Open Sud de France.
Berdych has made an encouraging start to the season after a long spell out with a back injury last year, but was made to work for a 5-7, 6-3, 6-3 victory in Montpellier on Tuesday.
The former world number four had a first-serve percentage of only 49 and double-faulted eight times, yet he was able to fight back and move into the second round.
Berdych will now face Benoit Paire after the eighth seed saw off Evgeny Donskoy 7-5, 6-3 in his homeland.
Nicolas Mahut completed a career men's doubles Grand Slam at the Australian Open, but was beaten in straight sets by Filip Krajinovic on home soil.
Pierre-Hugues Herbert, Antoine Hoang and Ernests Gulbis were the other first-round winners on day two of the indoor hard-court event.
Gael Monfils maintained his perfect record against Viktor Troicki with a 6-3, 6-4 victory in the first round of the Sofia Open.
The flamboyant Frenchman has now won five out of five contests with wildcard Troicki and will take on Laslo Djere or Mikhail Kukushkin in round two.
Matteo Berrettini will face top seed Karen Khachanov after beating Denis Istomin 6-4 7-6 (9-7), while Jan-Lennard Struff set up a meeting with Australian Open semi-finalist Stefanos Tsitsipas by overcoming Stefano Travaglia.
Robin Haase, Daniel Brands and Yannick Maden also moved into the last 16.