Former champion Stan Wawrinka was taken to four sets before winning his first match since knee surgery in July at the Australian Open on Tuesday.
The three-time Grand Slam winner downed Ricardas Berankis 6-3, 6-4, 2-6, 7-6 (7/2) on Hisense Arena.
It was a confidence booster for the 2014 Melbourne Park champion who had a troubled lead-in to the year's opening Grand Slam, pulling out of an exhibition event in Abu Dhabi.
The Swiss star, who defeated Rafael Nadal to win in 2014, has slipped to nine in the world rankings, having not played since his first-round Wimbledon loss to Russian Daniil Medvedev six months ago.
"It was a tough battle and I'm really happy to win my first match here after six months out," Wawrinka said.