Ana Ivanovic opened her title defence with a two hours struggle to overcome Italian Sara Errani 7-6 (7-3), 6-3 in the French Open in Paris on Sunday.
The eighth-seeded Serb who missed the past few weeks due to a leg injury, was made to fight by the number 44 in their first meeting.
Ivanovic needed 72 minutes to get through a torturous opening set, requiring three set points to take the match lead.
The favourite who has not made a huge impression since winning Roland Garros a year ago over Dinara Safina, the current number one, broke open the second set with breaks in the third and fifth games to eventually sprint to victory.
But there was still a detour as Errani broke while Ivanovic was serving for the win, the seed's seventh double-faults setting up two break points.
The Italian converted on the second but finally went down a game later after salvaging two match points before Ivanovic fired an overhead winner into the corner.
In other early results on the fourth year of Sunday starts, China's Li Na advanced over Marta Domachowska of Poland 6-4, 6-2 while Swiss Timea Bacsinszky staged a fightback for the first French defeat of the fortnight over Emilie Loit 4-6, 6-4, 6-1.