Stan Wawrinka survived a sloppy start to his French Open defence as he came through in five sets against Lukas Rosol on Monday to reach the second round.
The world number four and third seed has been in poor form leading up to the second grand slam of the year, although he did win the Geneva Open last week.
And he endured further struggles on Court Philippe Chatrier, with Rosol - a winner over Rafael Nadal at Wimbledon in 2012 - looking capable of springing another shock for long periods.
But Wawrinka eventually found his rhythm and his fabled backhand, claiming a 4-6 6-1 3-6 6-3 6-4 victory in a touch over three hours to avoid becoming the first defending champion to lose in the opening round.
Having been forced to wait for his match to start due to inclement weather at Roland Garros, Wawrinka struggled to adapt to the conditions and world number 59 Rosol took advantage thanks to a combination of power and impressive play at the net.
The Czech needed only one break to secure the first set but the tide looked to be turning in favour of Wawrinka as he surged to the second in just 35 minutes.
However, any hope Wawrinka had of quickly turning things around was extinguished by an error-strewn third-set showing in which he committed 13 unforced errors.
The Swiss' lack of poise put Rosol a set away from a stunning triumph but Wawrinka displayed excellent resiliency in the fourth, staving off two break points in a game that featured a 31-shot rally to go 3-2 up.
A stunning backhand pass brought the break that forced the decider and, after Rosol fired into the net to cede the initiative in the fifth, it was relatively smooth sailing for Wawrinka as he wrapped up the win with a backhand volley.