Defending Madrid Open champion Aryna Sabalenka battled past Magda Linette 6-4, 3-6, 6-3 on Friday to reach the third round.
The Australian Open winner has been in poor form since then and her Polish opponent fought well in the two hour nine minute contest.
Big-hitter Sabalenka, ranked second in the world, started well with a decisive break in the third game.
However Linette forced the Belarusian to scramble in the second set, breaking to love and then consolidating for a 4-1 lead.
The 32-year-old Pole carved out three break points in the sixth game but although she could not take them, eventually steered the match to a deciding third set.
Two-time Grand Slam champion Sabalenka saved two break points in the first game and another in the seventh to stay on serve.
The 25-year-old then opened up a break point of her own, only her fifth of the match, converting it with a fortunate net cord for a 5-3 lead.
Sabalenka wrapped up her narrow victory over the world number 48 by smashing down an ace and will face Katie Boulter or Robin Montgomery in the third round.
