Iga Swiatek was firmly tested for the first time since her win streak began but she managed to overcome Danka Kovinic to take it to 31 matches.
The world no.1 managed to secure a 6-3, 7-5 straight sets win in an hour and 30 minutes in a match that was tougher than the scoreline looks.
Swiatek, the champion here in 2020, has now reached the second week in all four of her Roland Garros appearances, and she has won 17 of her 19 matches at the tournament.
Kovinic, the first Montenegrin to reach the third round at Roland Garros, delivered a valiant performance that meant Swiatek could not repeat the smooth sailing of her opening two rounds.
The Pole took a 3-0 lead but Kovinic denied her any easy points as the World No.1 needed six breakpoints and 13 minutes to capture the first break.
Swiatek then let a 4-2, 40-0 lead slip amid a flurry of loose forehands that allowed Kovinic to get back on serve.
But having achieved this, she immediately relinquished her momentum with four cheap unforced errors to gift the break back to Swiatek.
Swiatek then enjoyed her least troublesome passage of play as she built a 4-1 double-break lead in the second set, only for her forehand to quit on her again.
A cascade of errors from that wing opened the door again for Kovinic and the former World No.46 ran off four straight games.
Swiatek steadied herself while Kovinic relapsed into errors.
Down 5-4, Swiatek delivered two solid service games around a timely break of the Kovinic serve to advance to the fourth round.
Swiatek will next face either Alizé Cornet or rising 19-year-old Zheng Qinwen.
The Iga Swiatek win streak stretches back to February and encompasses titles in Doha, Indian Wells, Miami, Stuttgart, and Rome,
As it stands, it is the fourth-longest of the 21st century with the 20-year-old being one win away from tying Justine Henin’s 32 in 2007-08; a final would equal Serena Williams’s 34 in 2013, and a title would put her level with Venus Williams’s 35 in 2000.
